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BCR-ABL
The Philadelphia chromosome or Philadelphia translocation (Ph) is a specific genetic abnormality in chromosome 22 of leukemia cancer cells (particularly chronic myeloid leukemia (CML) cells). This chromosome is defective and unusually short because of reciprocal translocation, t(9;22)(q34;q11), of genetic material between chromosome 9 and chromosome 22, and contains a fusion gene called ''BCR-ABL1''. This gene is the ''ABL1'' gene of chromosome 9 juxtaposed onto the breakpoint cluster region '' BCR'' gene of chromosome 22, coding for a hybrid protein: a tyrosine kinase signaling protein that is "always on", causing the cell to divide uncontrollably by interrupting the stability of the genome and impairing various signaling pathways governing the cell cycle. The presence of this translocation is required for diagnosis of CML; in other words, all cases of CML are positive for ''BCR-ABL1''. (Some cases are confounded by either a cryptic translocation that is invisible on G-banded c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chronic Myeloid Leukemia
Chronic myelogenous leukemia (CML), also known as chronic myeloid leukemia, is a cancer of the white blood cells. It is a form of leukemia characterized by the increased and unregulated growth of myeloid cells in the bone marrow and the accumulation of these cells in the blood. CML is a clonal bone marrow stem cell disorder in which a proliferation of mature granulocytes (neutrophils, eosinophils and basophils) and their precursors is found. It is a type of myeloproliferative neoplasm associated with a characteristic chromosomal translocation called the Philadelphia chromosome. CML is largely treated with targeted drugs called tyrosine-kinase inhibitors (TKIs) which have led to dramatically improved long-term survival rates since 2001. These drugs have revolutionized treatment of this disease and allow most patients to have a good quality of life when compared to the former chemotherapy drugs. In Western countries, CML accounts for 15–25% of all adult leukemias and 14% of leuke ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ABL (gene)
Tyrosine-protein kinase ABL1 also known as ABL1 is a protein that, in humans, is encoded by the ''ABL1'' gene (previous symbol ''ABL'') located on chromosome 9. c-Abl is sometimes used to refer to the version of the gene found within the mammalian genome, while v-Abl refers to the viral gene, which was initially isolated from the Abelson murine leukemia virus. Function The ''ABL1'' proto-oncogene encodes a cytoplasmic and nuclear protein tyrosine kinase that has been implicated in processes of cell differentiation, cell division, cell adhesion, and stress response such as DNA repair. Activity of ABL1 protein is negatively regulated by its SH3 domain, and deletion of the SH3 domain turns ABL1 into an oncogene. The t(9;22) translocation results in the head-to-tail fusion of the '' BCR'' and ''ABL1'' genes, leading to a fusion gene present in many cases of chronic myelogenous leukemia. The DNA-binding activity of the ubiquitously expressed ABL1 tyrosine kinase is regulated by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BCR (gene)
The breakpoint cluster region protein (BCR) also known as renal carcinoma antigen NY-REN-26 is a protein that in humans is encoded by the ''BCR'' gene. ''BCR'' is one of the two genes in the ''BCR-ABL'' fusion protein, which is associated with the Philadelphia chromosome. Two transcript variants encoding different isoforms have been found for this gene. Function Although the BCR- ABL fusion protein has been much studied, the function of the normal BCR gene product is still not clear. The protein has serine/threonine kinase activity and is a guanine nucleotide exchange factor for the Rho family of GTPases including RhoA. Clinical significance A reciprocal translocation between chromosomes 22 and 9 produces the Philadelphia chromosome, which is often found in patients with chronic myelogenous leukemia. The chromosome 22 breakpoint for this translocation is located within the ''BCR'' gene. The translocation produces a fusion protein that is encoded by sequence from both ''BCR' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 kinases such as CSF1R, ABL, c-KIT, FLT3, and PDGFR-β. Specifically, it is used for chronic myelogenous leukemia (CML) and acute lymphocytic leukemia (ALL) that are Philadelphia chromosome-positive (Ph+), certain types of gastrointestinal stromal tumors (GIST), hypereosinophilic syndrome (HES), chronic eosinophilic leukemia (CEL), systemic mastocytosis, and myelodysplastic syndrome. Common side effects include vomiting, diarrhea, muscle pain, headache, and rash. Severe side effects may include fluid retention, gastrointestinal bleeding, bone marrow suppression, liver problems, and heart failure. Use during pregnancy may result in harm to the baby. Imatinib works by stopping the Bcr-Abl tyrosine-kinase. This can slow growth or result in p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 class of enzymes known as protein kinases which also attach phosphates to other amino acids such as serine and threonine. Phosphorylation of proteins by kinases is an important mechanism for communicating signals within a cell (signal transduction) and regulating cellular activity, such as cell division. Protein kinases can become mutated, stuck in the "on" position, and cause unregulated growth of the cell, which is a necessary step for the development of cancer. Therefore, kinase inhibitors, such as imatinib and osimertinib, are often effective cancer treatments. Most tyrosine kinases have an associated protein tyrosine phosphatase, which removes the phosphate group. Reaction Protein kinases are a group of enzymes that possess a catal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acute Lymphoblastic Leukemia
Acute lymphoblastic leukemia (ALL) is a cancer of the lymphoid line of blood cells characterized by the development of large numbers of immature lymphocytes. Symptoms may include feeling tired, pale skin color, fever, easy bleeding or bruising, enlarged lymph nodes, or bone pain. As an acute leukemia, ALL progresses rapidly and is typically fatal within weeks or months if left untreated. In most cases, the cause is unknown. Genetic risk factors may include Down syndrome, Li-Fraumeni syndrome, or neurofibromatosis type 1. Environmental risk factors may include significant radiation exposure or prior chemotherapy. Evidence regarding electromagnetic fields or pesticides is unclear. Some hypothesize that an abnormal immune response to a common infection may be a trigger. The underlying mechanism involves multiple genetic mutations that results in rapid cell division. The excessive immature lymphocytes in the bone marrow interfere with the production of new red blood cells, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fusion Gene
A fusion gene is a hybrid gene formed from two previously independent genes. It can occur as a result of translocation, interstitial deletion, or chromosomal inversion. Fusion genes have been found to be prevalent in all main types of human neoplasia. The identification of these fusion genes play a prominent role in being a diagnostic and prognostic marker. History The first fusion gene was described in cancer cells in the early 1980s. The finding was based on the discovery in 1960 by Peter Nowell and David Hungerford in Philadelphia of a small abnormal marker chromosome in patients with chronic myeloid leukemia—the first consistent chromosome abnormality detected in a human malignancy, later designated the Philadelphia chromosome. In 1973, Janet Rowley in Chicago showed that the Philadelphia chromosome had originated through a translocation between chromosomes 9 and 22, and not through a simple deletion of chromosome 22 as was previously thought. Several investigators in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mixed-phenotype Acute Leukemia
Mixed-phenotype acute leukemia (MPAL) is a group of blood cancers (leukemia) which have combined features of myeloid and lymphoid cancers. It is a rare disease, constituting about 2–5% of all leukemia cases. It mostly involve myeloid with either of T lymphocyte or B lymphocyte progenitors, but in rare cases all the three cell lineages. Knowledge on the cause, clinical features and cellular mechanism is poor, making the treatment and management (prognosis) difficult. The name "mixed-phenotype acute leukemia" was adopted by the World Health Organization in 2008 to include leukemias of ambiguous lineage, acute undifferentiated leukemias and natural killer lymphoblastic leukemias. According to WHO criteria, myeloid lineage is characterised by the presence of myeloperoxidase, while B and T lymphoid lineages are indicated by the expression of CD19 and cytoplasmic CD3. __TOC__ Molecular biology The fundamental feature of MPAL involves two types of tranlocations that occur in chromoso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acute Myelogenous Leukemia
Acute myeloid leukemia (AML) is a cancer of the myeloid line of blood cells, characterized by the rapid growth of abnormal cells that build up in the bone marrow and blood and interfere with normal blood cell production. Symptoms may include feeling tired, shortness of breath, easy bruising and bleeding, and increased risk of infection. Occasionally, spread may occur to the brain, skin, or gums. As an acute leukemia, AML progresses rapidly, and is typically fatal within weeks or months if left untreated. Risk factors include smoking, previous chemotherapy or radiation therapy, myelodysplastic syndrome, and exposure to the chemical benzene. The underlying mechanism involves replacement of normal bone marrow with leukemia cells, which results in a drop in red blood cells, platelets, and normal white blood cells. Diagnosis is generally based on bone marrow aspiration and specific blood tests. AML has several subtypes for which treatments and outcomes may vary. The first-l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 phosphate group to the protein (phosphorylation), a step that TKIs inhibit. TKIs are typically used as anticancer drugs. For example, they have substantially improved outcomes in chronic myelogenous leukemia. They have also been used to treat other diseases, such as idiopathic pulmonary fibrosis. They are also called tyrphostins, the short name for "tyrosine phosphorylation inhibitor", originally coined in a 1988 publication, which was the first description of compounds inhibiting the catalytic activity of the epidermal growth factor receptor (EGFR). The 1988 study was the first demonstration of a systematic search and discovery of small-molecular-weight inhibitors of tyrosine phosphorylation, which do not inhibit protein kinases that phosph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 imatinib-resistant gastrointestinal stromal tumor (GIST) on January 26, 2006. Sunitinib was the first cancer drug simultaneously approved for two different indications. As of August 2021, sunitinib is available as a generic medicine in the US. Medical uses Gastrointestinal stromal tumor Like RCC, GIST does not generally respond to standard chemotherapy or radiation. Imatinib was the first cancer agent proven effective for metastatic GIST and represented a major development in the treatment of this rare but challenging disease. However, approximately 20% of patients do not respond to imatinib (early or primary resistance), and among those who do respond initially, 50% develop secondary imatinib resistance and disease progression within t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alternative Splicing
Alternative splicing, or alternative RNA splicing, or differential splicing, is an alternative splicing process during gene expression that allows a single gene to code for multiple proteins. In this process, particular exons of a gene may be included within or excluded from the final, processed messenger RNA (mRNA) produced from that gene. This means the exons are joined in different combinations, leading to different (alternative) mRNA strands. Consequently, the proteins translated from alternatively spliced mRNAs will contain differences in their amino acid sequence and, often, in their biological functions (see Figure). Biologically relevant alternative splicing occurs as a normal phenomenon in eukaryotes, where it increases the number of proteins that can be encoded by the genome. In humans, it is widely believed that ~95% of multi-exonic genes are alternatively spliced to produce functional alternative products from the same gene but many scientists believe that most o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
