Epithelioid Sarcoma
   HOME

TheInfoList



OR:

Epithelioid sarcoma is a rare
soft tissue sarcoma A soft-tissue sarcoma (STS) is a malignant tumour, a type of cancer, that develops in soft tissue. A soft tissue sarcoma is often a painless mass that grows slowly over months or years. They may be superficial or deep-seated. Any such unexplained ...
arising from
mesenchymal Mesenchyme () is a type of loosely organized animal embryonic connective tissue of undifferentiated cells that give rise to most tissues, such as skin, blood or bone. The interactions between mesenchyme and epithelium help to form nearly every o ...
tissue and characterized by epithelioid-like features. It accounts for less than 1% of all soft tissue sarcomas. It was first clearly characterized by F.M. Enzinger in 1970. It commonly presents itself in the
distal Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...
limbs (fingers, hands, forearms, or feet) of young adults as a small, soft mass or a series of bumps. A
proximal Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...
version has also been described, frequently occurring in the upper extremities. Rare cases have been reported in the pelvis, vulva, penis, and spine. Histologically, epithelioid sarcoma forms nodules with central necrosis surrounded by bland, polygonal cells with eosinophilic cytoplasm and peripheral spindling. Epithelioid sarcomas typically express
vimentin Vimentin is a structural protein that in humans is encoded by the ''VIM'' gene. Its name comes from the Latin ''vimentum'' which refers to an array of flexible rods. Vimentin is a type III intermediate filament (IF) protein that is expressed ...
,
cytokeratins Cytokeratins are keratin proteins found in the intracytoplasmic cytoskeleton of epithelial tissue. They are an important component of intermediate filaments, which help cells resist mechanical stress. Expression of these cytokeratins within epi ...
,
epithelial membrane antigen Mucin short variant S1, also called polymorphic epithelial mucin (PEM) or epithelial membrane antigen (EMA), is a mucin encoded by the ''MUC1'' gene in humans. Mucin short variant S1 is a glycoprotein with extensive O-linked glycosylation of its e ...
, and
CD34 CD34 is a transmembrane phosphoglycoprotein protein encoded by the CD34 gene in humans, mice, rats and other species. CD34 derives its name from the cluster of differentiation protocol that identifies cell surface antigens. CD34 was first descri ...
, whereas they are usually negative for S100,
desmin Desmin is a protein that in humans is encoded by the ''DES'' gene. Desmin is a muscle-specific, type III intermediate filament that integrates the sarcolemma, Z disk, and nuclear membrane in sarcomeres and regulates sarcomere architecture. Str ...
, and
FLI1 Friend leukemia integration 1 transcription factor (FLI1), also known as transcription factor ERGB, is a protein that in humans is encoded by the ''FLI1'' gene, which is a proto-oncogene. Function Fli-1 is a member of the ETS transcription fa ...
(FLI-1). They typically stain positive for CA125. Epithelioid sarcoma most commonly strikes young adults, yet no age group is immune. The disease has a tendency to develop local recurrences and
metastasis Metastasis is a pathogenic agent's spread from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, then, ...
thereafter to regional lymph nodes, lung, bone, brain, and other locations, including the scalp. Generally speaking, epithelioid sarcoma has a high rate of relapse after initial treatment and tends to recur locally (at or near the original tumor site). Epithelioid sarcoma also demonstrates lymphatic spread (in 22-48% of cases), and metastasis (in 21-63% of cases). These events, as well as advanced stage (progression) and grade (aggressiveness), are predictive of an overall worse outcome. The overall five-year survival rate for epithelioid sarcoma is anywhere from 25 to 78%. Importantly, the 10-year and 15-year survival rate drops off significantly. Associated with a more positive outcome are younger age, female vs. male sex, distal vs. proximal location, smaller tumor size, and negative margins upon tumor resection.


Signs and symptoms

Epithelioid sarcoma is a slow-growing and relatively painless tumor, often resulting in a lengthy period of time between presentation and diagnosis. Due to its ambiguity, it is often misdiagnosed, mistaken as a persistent wart or cyst. It most commonly presents itself in the
distal Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...
limbs (fingers, hands, forearms, or feet) as a small, soft mass or a series of bumps. It is most often described as a firm-to-hard palpable mass, either in the deep soft tissue or in the dermis. Often, ulcerate causing a mistaken diagnosis of a poorly healing traumatic wound or wart. About 13% of patients will present with multifocal tumors, and about 13% of patients will present with metastatic disease.


Genetics

The most common genetic mutation (found in 80-90% of epithelioid sarcomas) is the inactivation of the
SMARCB1 SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily B member 1 is a protein that in humans is encoded by the ''SMARCB1'' gene. Function The protein encoded by this gene is part of a complex that relieves repressiv ...
gene, or the loss of INI-1 function, which is thought to be a major contributor to disease progression. Epithelioid sarcoma typically contains chromosome 22q11.2 mutations or deletions and 8q gains, particularly i(8) (>q10). Aberrations of 18q and 8q, as well as recurrent gains at 11q13, have also been observed. The SMARCB1 gene (also termed BAF47, INI1, or hSNF5) is located on chromosome
22q11.2 DiGeorge syndrome, also known as 22q11.2 deletion syndrome, is a syndrome caused by a microdeletion on the long arm of chromosome 22. While the symptoms can vary, they often include congenital heart problems, specific facial features, frequent i ...
and codes for a member of the
SWI/SNF In molecular biology, SWI/SNF (SWItch/Sucrose Non-Fermentable), is a subfamily of ATP-dependent chromatin remodeling complexes, which is found in eukaryotes. In other words, it is a group of proteins that associate to remodel the way DNA is packa ...
chromatin remodeling complex. Loss of SMARCB1 function is the most common genetic mutation observed in epithelioid sarcoma, and this dysfunction is likely a major driver of disease progression. SMARCB1 is a core protein subunit of the 15 subunit SWI/SNF (or BAF) complex involved in regulating the nucleosome architecture of our genome and has been shown to be a potent
tumor suppressor gene A tumor suppressor gene (TSG), or anti-oncogene, is a gene that regulates a cell during cell division and replication. If the cell grows uncontrollably, it will result in cancer. When a tumor suppressor gene is mutated, it results in a loss or red ...
, meaning that its primary role is to control cell division and to even halt division under appropriate circumstances (i.e. signals to over-replicate). As this tumor suppressor is commonly inactivated in epithelioid sarcoma, cell division can fail to appropriately halt, resulting in unregulated cellular growth and the formation of cancer tumors. Several research teams are currently developing techniques to reverse this loss of genetic function characteristic of epithelioid sarcoma.


Molecular biology


VEGF

VEGF Vascular endothelial growth factor (VEGF, ), originally known as vascular permeability factor (VPF), is a signal protein produced by many cells that stimulates the formation of blood vessels. To be specific, VEGF is a sub-family of growth factors, ...
(vascular endothelial growth factor) is often over-expressed in epithelioid sarcoma. This is a critical pathway in
angiogenesis Angiogenesis is the physiological process through which new blood vessels form from pre-existing vessels, formed in the earlier stage of vasculogenesis. Angiogenesis continues the growth of the vasculature by processes of sprouting and splitting ...
, a process that cancer cells use to form new blood vessels, which provide necessary elements to the
tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...
for tumor survival. Anti-VEGF agents such as
pazopanib Pazopanib, sold under the brand name Votrient, is an anti-cancer medication marketed worldwide by Novartis. It is a potent and selective multi-targeted receptor tyrosine kinase inhibitor that blocks tumour growth and inhibits angiogenesis. It has ...
have shown promise across several different carcinomas and in soft tissue sarcomas. In one case study, a patient with advanced metastatic vulvar epithelioid sarcoma showed a partial resolution of both lung and pleural metastases when pazopanib was administered, whereas all other therapies had failed


MET

MET (mesenchymal to epithelial transition) is another biological pathway that is likely involved in the development and progression of epithelioid sarcoma. c-MET is a
tyrosine kinase A tyrosine kinase is an enzyme that can transfer a phosphate group from ATP to the tyrosine residues of specific proteins inside a cell. It functions as an "on" or "off" switch in many cellular functions. Tyrosine kinases belong to a larger cla ...
oncogene An oncogene is a gene that has the potential to cause cancer. In tumor cells, these genes are often mutated, or expressed at high levels.
, and its signaling pathway has been implicated in a variety of malignancies, including many cancers.


Sonic hedgehog and Notch

The
Sonic hedgehog Sonic hedgehog protein (SHH) is encoded for by the ''SHH'' gene. The protein is named after the character ''Sonic the Hedgehog''. This signaling molecule is key in regulating embryonic morphogenesis in all animals. SHH controls organogenesis and ...
and
Notch signaling pathway The Notch signaling pathway is a highly Conserved sequence, conserved cell signaling system present in most animals. Mammals possess four different Notch proteins, notch receptors, referred to as NOTCH1, NOTCH2, Notch 3, NOTCH3, and NOTCH4. The ...
s are also suspected to be up-regulated in epithelioid sarcoma. These cell signaling pathways control cellular proliferation and differentiation. They are also involved in
cancer stem cell Cancer stem cells (CSCs) are cancer cells (found within tumors or hematological cancers) that possess characteristics associated with normal stem cells, specifically the ability to give rise to all cell types found in a particular cancer sample. ...
coordination and disease invasiveness and metastasis. Hhat inhibitors (such as RU-SKI 43) block the Sonic hedgehog signaling pathway by inhibiting hedgehog palmitoyl acytl-transferase. Current trials are investigating Notch inhibitors against epithelioid sarcoma.


mTOR

The frequent hyperactivation of
mTOR The mammalian target of sirolimus, rapamycin (mTOR), also referred to as the mechanistic target of rapamycin, and sometimes called FK506-binding protein 12-rapamycin-associated protein 1 (FRAP1), is a kinase that in humans is encoded by the ''MT ...
(mammalian target of rapamycin) signaling has also been observed in epithelioid sarcoma. The mTOR pathway has been described as a “master switch” for cellular
catabolism Catabolism () is the set of metabolic pathways that breaks down molecules into smaller units that are either oxidized to release energy or used in other anabolic reactions. Catabolism breaks down large molecules (such as polysaccharides, lipids, ...
and
anabolism Anabolism () is the set of metabolic pathways that construct molecules from smaller units. These reactions require energy, known also as an endergonic process. Anabolism is the building-up aspect of metabolism, whereas catabolism is the breaking-do ...
, and it can enhance
cell cycle progression The cell cycle, or cell-division cycle, is the series of events that take place in a cell that cause it to divide into two daughter cells. These events include the duplication of its DNA (DNA replication) and some of its organelles, and subse ...
, cell survival, and block normal cell death (
apoptosis Apoptosis (from grc, ἀπόπτωσις, apóptōsis, 'falling off') is a form of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death. These changes incl ...
). It has been demonstrated that simply blocking mTOR signaling can result in the reactivation of the
AKT Protein kinase B (PKB), also known as Akt, is the collective name of a set of three serine/threonine-specific protein kinases that play key roles in multiple cellular processes such as glucose metabolism, apoptosis, cell proliferation, tran ...
pathway, negating much of the anti-mTOR's efficacy. This reactivation of AKT has been shown to be c-MET-dependent, resulting in the rationale that blocking both mTOR and c-MET concurrently would show increased efficacy.


EGFR

The over-expression of
epidermal growth factor receptor The epidermal growth factor receptor (EGFR; ErbB-1; HER1 in humans) is a transmembrane protein that is a receptor for members of the epidermal growth factor family (EGF family) of extracellular protein ligands. The epidermal growth factor recept ...
(EGFR) has been reported in a majority of epithelioid sarcomas. EGFR is a member of the HER receptor family. Upon
ligand binding In biochemistry and pharmacology, a ligand is a substance that forms a complex with a biomolecule to serve a biological purpose. The etymology stems from ''ligare'', which means 'to bind'. In protein-ligand binding, the ligand is usually a mo ...
, EGFR phosphorylation triggers the activation of downstream signaling pathways involved in critical cellular functions such as proliferation, survival, and
angiogenesis Angiogenesis is the physiological process through which new blood vessels form from pre-existing vessels, formed in the earlier stage of vasculogenesis. Angiogenesis continues the growth of the vasculature by processes of sprouting and splitting ...
.
In-vitro ''In vitro'' (meaning in glass, or ''in the glass'') studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called " test-tube experiments", these studies in biology and ...
and
in-vivo Studies that are ''in vivo'' (Latin for "within the living"; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, and pl ...
laboratory experiments have demonstrated that the blockade of EGFR in epithelioid sarcoma results in decreased cell proliferation, increased apoptosis, and abrogated invasion and migration capacities. While the simple blockade of EGFR with a single agent has shown limited results in the clinical setting, when used as part of a combination regime (where an EGFR inhibitor is combined with an mTOR inhibitor), a
synergism In Christian theology, synergism is the position of those who hold that salvation involves some form of cooperation between divine grace and human freedom. Synergism is upheld by the Roman Catholic Church, Orthodox Churches, Anabaptist Churches ...
has been observed, and superior tumor growth inhibition has been demonstrated.


CD109

CD109 is often expressed in advanced epithelioid sarcoma and is thought to mark the
cancer stem cell Cancer stem cells (CSCs) are cancer cells (found within tumors or hematological cancers) that possess characteristics associated with normal stem cells, specifically the ability to give rise to all cell types found in a particular cancer sample. ...
(or cancer initiating cell) of the disease. Its level of expression has also been shown to be predictive of outcome. Cancer stem cells are a small population of tumor cells characterized by general chemo-resistance, the ability to self-renew, multi-differentiation potential, dormancy capabilities, and tumorigenesis. Therefore, cancer stem cells are thought to play key roles in the progression and relapse of cancer.


Cyclin D1

Cyclin D1 Cyclin D1 is a protein that in humans is encoded by the ''CCND1'' gene. Gene expression The CCND1 gene encodes the cyclin D1 protein. The human CCND1 gene is located on the long arm of chromosome 11 (band 11q13). It is 13,388 base pairs lon ...
is a protein requisite for cell cycle progression and has been shown to be up-regulated in epithelioid sarcoma. Cyclin D-1 is a regulator of cyclin-dependent kinases ( CDK4 and
CDK6 Cell division protein kinase 6 (CDK6) is an enzyme encoded by the ''CDK6'' gene. It is regulated by cyclins, more specifically by Cyclin D proteins and Cyclin-dependent kinase inhibitor proteins. The protein encoded by this gene is a member of th ...
). It has been shown to interact with the
retinoblastoma protein The retinoblastoma protein (protein name abbreviated pRb; gene name abbreviated ''Rb'', ''RB'' or ''RB1'') is a proto-oncogenic tumor suppressor protein that is dysfunctional in several major cancers. One function of pRb is to prevent excessive ...
(a tumor suppressor gene), CDK4 and CDK6,
thyroid hormone receptor beta Thyroid hormone receptor beta (TR-beta) also known as nuclear receptor subfamily 1, group A, member 2 (NR1A2), is a nuclear receptor protein that in humans is encoded by the ''THRB'' gene. Function The protein encoded by this gene is a nuclear ...
, and
nuclear receptor coactivator 1 The nuclear receptor coactivator 1 (''NCOA1'') is a transcriptional coregulatory protein that contains several nuclear receptor interacting domains and an intrinsic histone acetyltransferase activity. NCOA1 is recruited to DNA promotion sites by ...
, among others. Cyclin D and CDKs promote cell cycle progression by releasing
transcription factors In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence. The func ...
that are important for the initiation of
DNA replication In molecular biology, DNA replication is the biological process of producing two identical replicas of DNA from one original DNA molecule. DNA replication occurs in all living organisms acting as the most essential part for biological inheritanc ...
. Abnormal levels of cyclin D-1 may promote rapid cell division in epithelioid sarcoma.


Diagnosis

Tissue
biopsy A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a diseas ...
is the diagnostic modality of choice. Due to a high incidence of lymph node involvement, a sentinel lymph node biopsy is often performed. A common characteristic of epithelioid sarcoma (observed in 80% of all cases) is the loss of function of the
SMARCB1 SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily B member 1 is a protein that in humans is encoded by the ''SMARCB1'' gene. Function The protein encoded by this gene is part of a complex that relieves repressiv ...
gene (also termed BAF47, INI1, or hSNF5). Immunohistochemical staining of INI1 is available and can be used for the diagnosis of epithelioid sarcoma.
MRI Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves ...
is the diagnostic modality of choice for imaging prior to biopsy and pathologic diagnosis, with the primary role being the determination of anatomic boundaries.


Staging

The staging for epithelioid sarcoma takes into account size and location of the primary tumor, lymph node involvement, presence and location of metastasis, and histologic grade (a measure of disease aggressiveness)


Treatment

Surgical resection of the tumor with wide margins remains the preferred method of treatment, and has shown the most success against the disease. Recently, limb-sparing surgery has been explored with moderate success. In cases of advanced, recurrent, or metastasized disease, or if the tumor is inoperable, chemotherapy and radiation are the standard of care, although the overall success rates with these remains low. In January 2020, The U.S. Food and Drug Administration approved Tazverik (tazemetostat), a compound that blocks the
EZH2 Enhancer of zeste homolog 2 (EZH2) is a histone-lysine N-methyltransferase enzyme ( EC 2.1.1.43) encoded by gene, that participates in histone methylation and, ultimately, transcriptional repression. EZH2 catalyzes the addition of methyl groups ...
methyltransferase for the treatment epithelioid sarcoma in patients aged 16 years and older with either metastatic or locally advanced (unable to be completely removed surgically) disease. The effectiveness of tazemetostat is further reinforced by real world report recently published by Dr Sameer Rastogi et al.


Prognosis

The 5-year survival rate for epithelioid sarcoma patients is 50-70%, and the 10-year survival rate is 42-55%. Children with epithelioid sarcoma tend to have slightly better outcomes than adults, with 5 year survival rates around 65%. Pediatric patients also tend to display less lymphatic spread and metastasis. In addition to stage and grade of the tumor, gender, site, age at diagnosis, tumor size and microscopic pathology have all been shown to affect prognosis. Advanced stage and grade are associated with worse outcomes. Females tend to have more favorable outcomes than males, proximal cases show worse outcomes than distal cases, and younger age is associated with more positive outcomes. Tumors more than 2 cm in diameter and tumors with
necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated dige ...
and
vascular invasion Lymphovascular invasion (LVI or lymphovascular space invasion) is the invasion (cancer), invasion of a cancer to the blood vessels and/or lymphatic system, lymphatics. Terminology Lymph: A clear or white fluid that travels through vessels, moves w ...
have been correlated with a worse outcome. The gold standard for chemotherapy is a combination of
doxorubicin Doxorubicin, sold under the brand name Adriamycin among others, is a chemotherapy medication used to treat cancer. This includes breast cancer, bladder cancer, Kaposi's sarcoma, lymphoma, and acute lymphocytic leukemia. It is often used togeth ...
and
ifosfamide Ifosfamide (IFO), sold under the brand name Ifex among others, is a chemotherapy medication used to treat a number of types of cancer. This includes testicular cancer, soft tissue sarcoma, osteosarcoma, bladder cancer, small cell lung cancer, cer ...
. However, recent studies have suggested that the addition of ifosfamide to doxorubicin does not necessarily lead to an increase in overall survival.
Etoposide Etoposide, sold under the brand name Vepesid among others, is a chemotherapy medication used for the treatments of a number of types of cancer including testicular cancer, lung cancer, lymphoma, leukemia, neuroblastoma, and ovarian cancer. It is ...
,
vincristine Vincristine, also known as leurocristine and marketed under the brand name Oncovin among others, is a chemotherapy medication used to treat a number of types of cancer. This includes acute lymphocytic leukemia, acute myeloid leukemia, Hodgkin's ...
,
dactinomycin Dactinomycin, also known as actinomycin D, is a chemotherapy medication used to treat a number of types of cancer. This includes Wilms tumor, rhabdomyosarcoma, Ewing's sarcoma, trophoblastic neoplasm, testicular cancer, and certain types of ovari ...
, and
cyclophosphamide Cyclophosphamide (CP), also known as cytophosphane among other names, is a medication used as chemotherapy and to suppress the immune system. As chemotherapy it is used to treat lymphoma, multiple myeloma, leukemia, ovarian cancer, breast cancer ...
have also traditionally been given. Newer chemotherapies, such as
gemcitabine Gemcitabine, with brand names including Gemzar, is a chemotherapy medication. It treats cancers including testicular cancer, breast cancer, ovarian cancer, non-small cell lung cancer, pancreatic cancer, and bladder cancer. It is administered by i ...
and
pazopanib Pazopanib, sold under the brand name Votrient, is an anti-cancer medication marketed worldwide by Novartis. It is a potent and selective multi-targeted receptor tyrosine kinase inhibitor that blocks tumour growth and inhibits angiogenesis. It has ...
, are currently being tested in clinical trials.
Radiation therapy Radiation therapy or radiotherapy, often abbreviated RT, RTx, or XRT, is a therapy using ionizing radiation, generally provided as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator. Radia ...
is also a treatment option when tumors are deemed inoperable or wide surgical margins are not achievable. Radiation therapy in combination with chemotherapy has so far resulted in only minimal improvements to response rates. Trials with
brachytherapy Brachytherapy is a form of radiation therapy where a sealed radiation source is placed inside or next to the area requiring treatment. ''Brachy'' is Greek for short. Brachytherapy is commonly used as an effective treatment for cervical, prosta ...
(an internal radiation treatment that delivers a high dose of radiation directly to the tumor and is thought to have fewer long-term side effects) have produced some positive results.


Research

Epithelioid sarcoma (especially advanced stage, recurrent, or metastasized disease) has been shown to be resistant to traditional cancer therapies, necessitating further exploration of novel treatment methods and techniques. Because of the relatively poor response of epithelioid sarcoma to traditional cancer treatments (surgery, chemotherapy, and radiation), new treatment strategies are being looked to.


Chemotherapy

New chemotherapies are being explored in current clinical trials for epithelioid sarcoma, although, thus far, none has shown significant improvement over the efficacy of doxorubicin/ifosfamide. These new agents include gemcitabine, pazopanib, cixutumumab, temozolomide, dasatanib, bevacizumab, taxanes, and vinorelbine.
Aldoxorubicin Aldoxorubicin (INNO-206) is a tumor-targeted doxorubicin conjugate in development by CytRx. Specifically, it is the (6- maleimido caproyl) hydrazone of doxorubicin. Essentially, this chemical name describes doxorubicin attached to an acid-sensit ...
is a new
pro-drug A prodrug is a medication or compound that, after intake, is metabolized (i.e., converted within the body) into a pharmacologically active drug. Instead of administering a drug directly, a corresponding prodrug can be used to improve how the drug ...
of doxorubicin. Doxorubicin is the standard of care for advanced or metastic epithelioid sarcoma, but has dose-limiting toxicities, namely acute and chronic
cardiac toxicity Cardiotoxicity is the occurrence of heart dysfunction as electric or muscle damage, resulting in heart toxicity. The heart becomes weaker and is not as efficient in pumping blood. Cardiotoxicity may be caused by chemotherapy (a usual example is th ...
. Doxorubicin has achieved response rates in the 12-23% range for patients with soft tissue sarcomas. Aldoxorubicin is a new version of doxorubicin that is designed to safely deliver a higher dose of the drug directly to the tumor, resulting in increased efficacy and less toxicity. It works by entering the bloodstream, binding to the
albumin Albumin is a family of globular proteins, the most common of which are the serum albumins. All the proteins of the albumin family are water-soluble, moderately soluble in concentrated salt solutions, and experience heat denaturation. Albumins ...
in the blood, traveling throughout the body, and releasing a doxorubicin payload when it encounters the acidic microenvironment of a tumor. Several phase I and II studies are ongoing, and, thus far at least, little if any cardiac toxicity has been observed. A maximum tolerated dose of aldoxorubicin has been established at 3.5 times the MTD of doxorubicin, and studies have indicated increased response rates for patients with soft tissue sarcomas. What is unknown at this time are the potential long-term side-effects of this increased dose of doxorubicin. Several studies have shown increased risk of the development of secondary cancers associated with exposure to high-dose anthracyclines (such as doxorubicin). TH-302 is another novel prodrug in current development. It targets
tumor hypoxia Tumor hypoxia is the situation where tumor cells have been deprived of oxygen. As a tumor grows, it rapidly outgrows its blood supply, leaving portions of the tumor with regions where the oxygen concentration is significantly lower than in health ...
, a common event in tumorigenesis where the tumor microenvironment is depleted of oxygen and becomes
hypoxic Hypoxia means a lower than normal level of oxygen, and may refer to: Reduced or insufficient oxygen * Hypoxia (environmental), abnormally low oxygen content of the specific environment * Hypoxia (medical), abnormally low level of oxygen in the t ...
. Hypoxic niches in tumors tend to harbor slower-growing cancer cells, making many chemotherapies ineffective in these areas. TH-302 directly targets these deep hypoxic regions, and once within them, it releases a cytotoxic payload of bromo-isophosphoramide mustard directly to the cancer cells. Given that epithelioid sarcoma is a slow-growing tumor, it is reasonable to hypothesize that ES tumors would be highly hypoxic and show a favorable response to TH-302. Several studies have observed increased efficacy of TH-302 when the hypoxic tumor microenvironment has been exasperated. Several phase I, II, and III trials with TH-302 and TH-302 in combination with doxorubicin are ongoing, and promising results have thus far been observed. Two phase 3 trials failed in 2015.


Immunotherapies

Immunotherapy Immunotherapy or biological therapy is the treatment of disease by activating or suppressing the immune system. Immunotherapies designed to elicit or amplify an immune response are classified as ''activation immunotherapies,'' while immunotherap ...
is the strategy of using the body's own immune system to fight cancer. It usually involves “training” or “tweaking” the immune system so that it can better recognize and reject cancer cells. Different immunotherapies can include manipulation of the body's
T-cells A T cell is a type of lymphocyte. T cells are one of the important white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell rec ...
,
NK cells Natural killer cells, also known as NK cells or large granular lymphocytes (LGL), are a type of cytotoxic lymphocyte critical to the innate immune system that belong to the rapidly expanding family of known innate lymphoid cells (ILC) and represen ...
, or
Dendritic cells Dendritic cells (DCs) are antigen-presenting cells (also known as ''accessory cells'') of the mammalian immune system. Their main function is to process antigen material and present it on the cell surface to the T cells of the immune system. The ...
so they are more effective against cancer cells. They can also include the administration of laboratory-produced
antibodies An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...
specific to tumor
antigens In immunology, an antigen (Ag) is a molecule or molecular structure or any foreign particulate matter or a pollen grain that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune response. ...
to create or boost an
immune response An immune response is a reaction which occurs within an organism for the purpose of defending against foreign invaders. These invaders include a wide variety of different microorganisms including viruses, bacteria, parasites, and fungi which could ...
. Vaccine therapy is perhaps the
immunotherapeutic Immunotherapy or biological therapy is the treatment of disease by activating or suppressing the immune system. Immunotherapies designed to elicit or amplify an immune response are classified as ''activation immunotherapies,'' while immunotherap ...
strategy with the most ongoing exploration in sarcomas at the current time, although, thus far at least, little evidence has emerged indicating that active vaccination alone can lead to tumor regression. Multiple techniques and treatment strategies are currently being studied in an effort to improve the objective response rate of vaccine therapy. Vaccines can deliver various tumor-associated factors (tumor antigens) to the immune system, resulting in a natural antibody and T-cell response to the tumor. Adoptive immunotherapy seeks to expand a population of the body's T-cells that will recognize a specific tumor antigen. T-cells can be harvested and then expanded and genetically manipulated to recognize certain tumor markers. In one case, a patient with advanced epithelioid sarcoma who had failed multiple therapies showed a strong response to expanded lymphocytes and natural killer cells.
Immune checkpoint inhibitor Cancer immunotherapy (sometimes called immuno-oncology) is the stimulation of the immune system to treat cancer, improving on the immune system's natural ability to fight the disease. It is an application of the fundamental research of cancer im ...
s have recently shown promise against several cancers and may hold promise against sarcomas as well. Tumors often evolve during disease progression, and they can develop an expression of inhibitory proteins that deter recognition by the immune system and allow the tumor to escape immune surveillance. By targeting these inhibitory proteins, a pathway is opened for the immune system to recognize the tumor. Two of these inhibitory proteins that have been studied recently are
CTLA-4 CTLA-4 or CTLA4 (cytotoxic T-lymphocyte-associated protein 4), also known as CD152 (cluster of differentiation 152), is a protein receptor that functions as an immune checkpoint and downregulates immune responses. CTLA-4 is constitutively expres ...
and PD1, and drugs targeting these proteins are in development and showing some promise.


Anti-angiogenic therapies

Several
anti-angiogenic An angiogenesis inhibitor is a substance that inhibits the growth of new blood vessels (angiogenesis). Some angiogenesis inhibitors are endogenous and a normal part of the body's control and others are obtained exogenously through pharmaceutical dru ...
agents are being explored in epithelioid sarcoma, a cancer that likely relies on angiogenesis for survival and progression. These agents interfere with various pro-angiogenic factors, several of which are known to be over-expressed in epithelioid sarcoma (VEGF and EGFR for example). Tumors require a blood supply to provide them with oxygen and nutrients necessary for their survival. As tumors expand and grow, they send out various signals (such as HIF1) that encourage new blood vessel development to the tumor. Anti-angiogenic agents, such as
bevacizumab Bevacizumab, sold under the brand name Avastin among others, is a medication used to treat a number of types of cancers and a specific eye disease. For cancer, it is given by slow injection into a vein (intravenous) and used for colon cancer, l ...
, attempt to slow or block the growth of tumors by essentially cutting off their blood supply.


Targeted therapies

Given the multiple genetic abnormalities and disrupted biological pathways observed in epithelioid sarcoma, drugs targeting these unique tumor characteristics are being looked at for more effective treatments.


Tyrosine kinase inhibitors

Tyrosine kinase inhibitors A tyrosine kinase inhibitor (TKI) is a pharmaceutical drug that inhibits tyrosine kinases. Tyrosine kinases are enzymes responsible for the activation of many proteins by signal transduction cascades. The proteins are activated by adding a phosph ...
(such as
sunitinib Sunitinib, sold under the brand name Sutent, is a medication used to treat cancer. It is a small-molecule, multi-targeted receptor tyrosine kinase (RTK) inhibitor that was approved by the FDA for the treatment of renal cell carcinoma (RCC) and i ...
,
pazopanib Pazopanib, sold under the brand name Votrient, is an anti-cancer medication marketed worldwide by Novartis. It is a potent and selective multi-targeted receptor tyrosine kinase inhibitor that blocks tumour growth and inhibits angiogenesis. It has ...
, and
dasatinib Dasatinib, sold under the brand name Sprycel among others, is a targeted therapy medication used to treat certain cases of chronic myelogenous leukemia (CML) and acute lymphoblastic leukemia (ALL). Specifically it is used to treat cases that ar ...
) have shown some effect against several cancer types, most notably
Imatinib Imatinib, sold under the brand names Gleevec and Glivec (both marketed worldwide by Novartis) among others, is an oral chemotherapy medication used to treat cancer. Imatinib is a small molecule inhibitor targeting multiple receptor tyrosine kin ...
-mesylate in
gastrointestinal stromal tumors Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. GISTs arise in the smooth muscle pacemaker interstitial cell of Cajal, or similar cells. They are defined as tumors whose behavior ...
(GISTs). Tyrosine kinase (a subclass of protein kinases) is an
enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
that transfers a
phosphate group In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phosphor ...
from an ATP molecule to a
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
in a cell. It functions as an “on” or “off” switch for many cellular functions, including signaling within the cell, and cell division. Tyrosine kinases can contain mutations that cause them to become constitutively active, or stuck in the “on” position, resulting in unregulated cell division (a hallmark of cancer). Tyrosine kinase Inhibitors block the action of these enzymes. Tyrosine kinase inhibitors have been shown to inhibit the VEGF, EGFR, and MET, pathways that are frequently over-expressed in epithelioid sarcoma. They also can be used against the
c-KIT Proto-oncogene c-KIT is the gene encoding the receptor tyrosine kinase protein known as tyrosine-protein kinase KIT, CD117 (cluster of differentiation 117) or mast/stem cell growth factor receptor (SCFR). Multiple transcript variants encoding diff ...
and
JAK-STAT signaling pathway The JAK-STAT signaling pathway is a chain of interactions between proteins in a cell, and is involved in processes such as immunity, cell division, cell death, and tumour formation. The pathway communicates information from chemical signals out ...
s, which are involved in many cancers and may be involved in epithelioid sarcoma.
Temsirolimus Temsirolimus, sold under the brand name Torisel, is an intravenous drug for the treatment of renal cell carcinoma (RCC), developed by Wyeth Pharmaceuticals and approved by the U.S. Food and Drug Administration (FDA) in May 2007, and was also appro ...
is a tyrosine kinase inhibitor that blocks the effects of the mTOR protein and inhibits the mTOR pathway. Because of crosstalk between cell signaling pathways, it has been shown that, while interfering with the mTOR pathway alone produces only limited results in halting tumorigenesis, inhibiting both the mTOR and the EGFR pathways concurrently shows an increased effect.


SINE

Selective inhibitors of nuclear export (
SINE In mathematics, sine and cosine are trigonometric functions of an angle. The sine and cosine of an acute angle are defined in the context of a right triangle: for the specified angle, its sine is the ratio of the length of the side that is oppo ...
) compounds, such as
selinexor Selinexor sold under the brand name Xpovio among others, is a selective inhibitor of nuclear export used as an anti-cancer medication. It works by blocking the action of exportin 1 and thus blocking the transport of several proteins involved in ...
and CBS9106, are being investigated in several sarcomas and have recently shown promising results across a broad spectrum of both
hematological malignancies Tumors of the hematopoietic and lymphoid tissues (American English) or tumours of the haematopoietic and lymphoid tissues (British English) are tumors that affect the blood, bone marrow, lymph, and lymphatic system. Because these tissues are all ...
and
solid tumors A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...
. These compounds work by blocking the export of tumor suppressor genes from the cell's nucleus to the cell's cytoplasm, where they are rendered nonfunctional. Exportin 1 (a.k.a. XPO1 or CRM1) is a nuclear export protein responsible for the export of over 200 proteins, including the vast majority of tumor suppressor proteins. For tumor suppressor genes to carry out their normal function (appropriately initiating apoptosis), they must be located in the nucleus of the cell. Many cancer cells have been shown to express high levels of exportin1, resulting in the increased export of tumor suppressor proteins out of the nucleus and therefore counteracting the natural apoptic processes that protect the body from cancer. SINE compounds prevent the transport of these tumor suppressor proteins out of the nucleus, allowing them to function normally and encourage apoptosis. Recently, researchers have observed a synergistic effect when using SINE compounds in combination with traditional chemotherapies (such as doxorubicin). It has been demonstrated that a loss of INI1 expression can result in the “unmasking” of a nuclear export signal, resulting in the transport of tumor suppressor proteins out of the nucleus of the cell, thus favoring tumorigenesis. It is therefore reasonable to suspect that a SINE inhibitor would show efficacy against epithelioid sarcoma, as the disease is characterized by a loss of INI1 function.


HDAC inhibitors

Histone deacetylase (
HDAC Histone deacetylases (, HDAC) are a class of enzymes that remove acetyl groups (O=C-CH3) from an ε-N-acetyl lysine amino acid on a histone, allowing the histones to wrap the DNA more tightly. This is important because DNA is wrapped around h ...
) inhibitors, such as
vorinostat Vorinostat (rINN) also known as Suberoylanilide hydroxamic acid ( suberoyl+anilide+hydroxamic acid abbreviated as SAHA) is a member of a larger class of compounds that inhibit histone deacetylases (HDAC). Histone deacetylase inhibitors (HDI) ha ...
, have shown some promise in epithelioid sarcoma. Researchers in Texas are investigating whether or not
HDAC inhibitors Histone deacetylase inhibitors (HDAC inhibitors, HDACi, HDIs) are chemical compounds that inhibit histone deacetylases. HDIs have a long history of use in psychiatry and neurology as mood stabilizers and anti-epileptics. More recently they are bei ...
can reverse the loss of INI1 function that is characteristic of epithelioid sarcoma. HDAC inhibitors work by blocking events involved in DNA replication and, therefore, in cell division. Blocking HDAC has been shown to encourage cancer cells to enter apoptosis. Several dietary
phytochemicals Phytochemicals are chemical compounds produced by plants, generally to help them resist fungi, bacteria and plant virus infections, and also consumption by insects and other animals. The name comes . Some phytochemicals have been used as poison ...
have been shown to be effective HDAC inhibitors. These include sulphorphane,
indole-3-carbinol Indole-3-carbinol ( C9 H9 N O), sometimes referred to as I3C, is produced by the breakdown of the glucosinolate glucobrassicin, which can be found at relatively high levels in cruciferous vegetables such as broccoli, cabbage, cauliflower, brusse ...
, and phenethyl isothiocyanates, found in broccoli, kale, and watercress, and epigallocatecehin-3-gallate, found in green tea.


CDK inhibitors

Because of the association (see above) with
cyclin D1 Cyclin D1 is a protein that in humans is encoded by the ''CCND1'' gene. Gene expression The CCND1 gene encodes the cyclin D1 protein. The human CCND1 gene is located on the long arm of chromosome 11 (band 11q13). It is 13,388 base pairs lon ...
CDK inhibitors are being studied.
palbociclib Palbociclib, sold under the brand name Ibrance among others, is a medication developed by Pfizer for the treatment of HR-positive and HER2-negative breast cancer. It is a selective inhibitor of the cyclin-dependent kinases CDK4 and CDK6. Pal ...
is a
CDK inhibitor A CDK (cyclin-dependent kinase) inhibitor is any chemical that inhibits the function of CDKs. They are used to treat cancers by preventing overproliferation of cancer cells. The US FDA approved the first drug of this type, palbociclib (Ibrance), ...
(approved for some
breast cancer Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, milk rejection, fluid coming from the nipple, a newly inverted nipple, or a re ...
). Other experimental CDK inhibitors include
abemaciclib Abemaciclib, sold under the brand name Verzenio among others, is a medication for the treatment of advanced or metastatic breast cancers. It was developed by Eli Lilly and it acts as a CDK inhibitor selective for CDK4 and CDK6. It was designa ...
and
ribociclib Ribociclib, sold under the brand name Kisqali and Kryxana marketed by Novartis, is an inhibitor of cyclin D1/CDK4 and CDK6, and is used for the treatment of certain kinds of breast cancer. on Kisqali. Accessed 2017-09-08. Ribociclib is a kinase in ...
.


Targeting the cancer stem cell

Cancer stem cells Cancer stem cells (CSCs) are cancer cells (found within tumors or hematological cancers) that possess characteristics associated with normal stem cells, specifically the ability to give rise to all cell types found in a particular cancer sample ...
(or cancer-initiating cells) are thought to be a small population of cells within the tumor that are directly responsible for tumor formation. They are thought to be resistant to treatment and to have the ability to form all the cells needed for tumor development. They are suspected to be a major contributing factor in cancer progression and relapse after treatment. Certain “stem-like” cells have been found in epithelioid sarcoma that are marked by CD109 (cluster of differentiation 109), providing a potentially drug-able target on the cancer stem cell for the disease. Certain challenges to targeting CD109 do exist, however, as CD109 is expressed in other areas of the body and not only in tumor cells.


Oncolytic viral therapy

Oncolytic viral therapy is an emerging cancer therapy that attempts to infect cancer cells with a genetically engineered virus that can penetrate the DNA of the cell. The virus then 1.) does direct damage to the cancer cell, 2.) is spread throughout the cells of the tumor via cellular (DNA) multiplication (tumor cell division and replication), and 3.) provides a target for a direct immune response from the patient. It has been noted that the therapeutic potential of
oncolytic virotherapy An oncolytic virus is a virus that preferentially infects and kills cancer cells. As the infected cancer cells are destroyed by oncolysis, they release new infectious virus particles or virions to help destroy the remaining tumour. Oncolytic viru ...
is not a simple consequence of the
cytopathic effect Cytopathic effect or cytopathogenic effect (abbreviated CPE) refers to structural changes in host cells that are caused by viral invasion. The infecting virus causes lysis of the host cell or when the cell dies without lysis due to an inability to ...
but strongly relies on the induction of an endogenous immune response against transformed cells. Superior anticancer effects have been observed when oncolytic viruses are engineered to express (or be co-administered with) immunostimulatory molecules such as GM-CSF. Telomelysin (OBP-301) is an adenovirus that targets
telomerase Telomerase, also called terminal transferase, is a ribonucleoprotein that adds a species-dependent telomere repeat sequence to the 3' end of telomeres. A telomere is a region of repetitive sequences at each end of the chromosomes of most euka ...
, an enzyme that is expressed in practically all cancer cells but not in normal cells. OBP-301 has been studied in epithelioid sarcoma and shown to promote apoptosis and cell death


CGTG-102

CGTG-102
(developed by Oncos Therapeutics) is an adenovirus currently in orphan drug status for soft tissue sarcomas. It is modified to selectively replicate in p16/Rb-defective cells, which include most human cancer cells. In addition, CGTG-102 codes for the granulocyte–macrophage colony-stimulating factor (
GM-CSF Granulocyte-macrophage colony-stimulating factor (GM-CSF), also known as colony-stimulating factor 2 (CSF2), is a monomeric glycoprotein secreted by macrophages, T cells, mast cells, natural killer cells, endothelial cells and fibroblasts that ...
), a potent immunostimulatory molecule. While the CGTG-102 oncolytic adenovirus has shown efficacy as a single agent against several soft tissue sarcomas, it would also be appealing to use in combination with other regimes, as
oncolytic virus An oncolytic virus is a virus that preferentially infects and kills cancer cells. As the infected cancer cells are destroyed by lysis#Oncolysis, oncolysis, they release new infectious virus particles or virus, virions to help destroy the remaining ...
es have demonstrated very little overlap in side effects with traditional therapies such as chemotherapy and radiation. CGTG-102 has recently been studied in combination with doxorubicin, and a synergistic effect was observed. At least part of doxorubicin's
mechanism of action In pharmacology, the term mechanism of action (MOA) refers to the specific biochemical interaction through which a drug substance produces its pharmacological effect. A mechanism of action usually includes mention of the specific molecular targe ...
is as an inducer of immunogenic cell death, and it has been suggested that immune response contributes to its overall anti-tumor activity. Doxorubicin has been shown to increase adenoviral replication in soft tissue sarcoma cells as well, potentially contributing to the observed synergistic effect in the virus/doxorubicin combination.


Additional images

Image: Epithelioid sarcoma - intermed mag.jpg , Intermed. mag. Image: Epithelioid sarcoma - high mag.jpg , High mag. Image: Epithelioid sarcoma - smarcb1 - high mag.jpg , High mag. (SMARCB1)


See also

*
Soft tissue sarcoma A soft-tissue sarcoma (STS) is a malignant tumour, a type of cancer, that develops in soft tissue. A soft tissue sarcoma is often a painless mass that grows slowly over months or years. They may be superficial or deep-seated. Any such unexplained ...
*
Sarcoma A sarcoma is a malignant tumor, a type of cancer that arises from transformed cells of mesenchymal (connective tissue) origin. Connective tissue is a broad term that includes bone, cartilage, fat, vascular, or hematopoietic tissues, and sarcom ...
*
Malignant rhabdoid tumour Malignant rhabdoid tumour (MRT) is a very aggressive form of tumour originally described as a variant of Wilms' tumour, which is primarily a kidney tumour that occurs mainly in children. MRT was first described as a variant of Wilms' tumour of th ...
* Atypical teratoid/rhabdoid tumour


References


Further reading

*


External links

{{Medical resources , DiseasesDB = , ICD10 = , ICD9 = , ICDO = {{ICDO, 8804, 3 , OMIM = , MedlinePlus = , eMedicineSubj = , eMedicineTopic = , MeshID = Sarcoma Dermal and subcutaneous growths