CKLF-like MARVEL transmembrane domain-containing protein 2 (i.e. CMTM2), previously termed chemokine-like factor superfamily 2 ( i.e. CKLFSF2), is a member of the
CKLF-like MARVEL transmembrane domain-containing family The CKLF-like MARVEL transmembrane domain-containing family (CMTM), previously termed the chemokine-like factor superfamily (CKLFSF), consists of 9 proteins, some of which have various protein isoform, isoforms due to alternative splicing of their r ...
(CMTM) of proteins. In humans, it is encoded by the ''CMTM2''
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
located in
band
Band or BAND may refer to:
Places
*Bánd, a village in Hungary
*Band, Iran, a village in Urmia County, West Azerbaijan Province, Iran
*Band, Mureș, a commune in Romania
* Band-e Majid Khan, a village in Bukan County, West Azerbaijan Province, I ...
22 on the
long (i.e. "q") arm of
chromosome 16
Chromosome 16 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 16 spans about 90 million base pair
A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting ...
.
CMTM2 protein is expressed in the
bone marrow
Bone marrow is a semi-solid tissue found within the spongy (also known as cancellous) portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production (or haematopoiesis). It is composed of hematopoietic ce ...
and various circulating
blood cells
A blood cell, also called a hematopoietic cell, hemocyte, or hematocyte, is a cell produced through hematopoiesis and found mainly in the blood. Major types of blood cells include red blood cells (erythrocytes), white blood cells (leukocytes), a ...
.
It is also highly expressed in testicular tissues:
The ''CMTM2'' gene and CMTM2 protein, it is suggested, may play an important role in
testicular
A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testost ...
development.
Studies find that the levels of CMTM2 protein in
hepatocellular carcinoma
Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer in adults and is currently the most common cause of death in people with cirrhosis. HCC is the third leading cause of cancer-related deaths worldwide.
It occurs in t ...
tissues of patients are lower higher than their levels in normal liver tissues.
CMTM2 protein levels were also lower in the hepatocellular carcinoma tissues that had a more aggressive pathology and therefore a possible poorer prognosis.
Finally, the forced overexpression of CMTM2 protein in cultured hepatocellular tumor cells inhibited their invasiveness and migration.
These findings suggest that CMTM2 protein suppresses the development and/or progression of hepatocellular carcinoma and therefore that the ''CMTM2'' gene acts as a
tumor suppressor
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 ...
in this cancer.
Patients with higher CMTM2 levels in their
linitis plastica
Linitis plastica is a widely used term for Brinton's disease (also known as leather bottle stomach), a morphological variant of diffuse (or infiltrating) stomach cancer. In some texts, the term is also used to describe the condition of a rigid, no ...
stomach cancer (i.e. a type of
gastric cancer
Stomach cancer, also known as gastric cancer, is a cancer that develops from the lining of the stomach. Most cases of stomach cancers are gastric carcinomas, which can be divided into a number of subtypes, including gastric adenocarcinomas. Lymph ...
also termed diffuse-type gastric cancer or diffuse type adenocarcinoma of the stomach) tissues had better prognoses than patients with lower CMTM2 levels in their linitis plastica tissues.
And, the ''CMTM2'' gene has been found to be more highly expressed in the
salivary gland
The salivary glands in mammals are exocrine glands that produce saliva through a system of ducts. Humans have three paired major salivary glands (parotid, submandibular, and sublingual), as well as hundreds of minor salivary glands. Salivary gla ...
adenoid cystic carcinoma
Adenoid cystic carcinoma is a rare type of cancer that can exist in many different body sites. This tumor most often occurs in the salivary glands, but it can also be found in many anatomic sites, including the breast, lacrimal gland, lung, brai ...
tissues of patients who did not develop tumor recurrences or perineural invasion of their carcinomas compared to the expression of this gene in patients whose adenoid cystic carcinoma tissues went on to develop these complications.
These findings suggest that the ''CMTM2'' gene may act as a tumor suppressor not only in hepatocellular carcinoma but also in linitis plastica and salivary gland adenoid cystic carcinoma. Further studies are needed to confirm these findings and determine if CMTM2 protein can serve as a marker for the severity of these three cancers and/or as a
therapeutic target for treating them.
References
Further reading
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External links
* {{UCSC gene info, CMTM2
Human proteins
Gene expression