The HOXB13 gene provides instructions for producing a protein that attaches (binds) to specific regions of DNA and regulates the activity of other genes. On the basis of this role, the protein produced from the HOXB13 gene is called a transcription factor. The HOXB13 protein is part of a large group of transcription factors called the homeobox protein family. The HOXB13 protein is thought to play a role in the development and maintenance of the skin. It also acts as a tumor suppressor, which means that it keeps cells from growing and dividing too fast or in an uncontrolled way.
The HOXB13 protein has a characteristic homeobox region called the homeodomain, which binds to DNA, and two other regions called MEIS interacting domains. The MEIS interacting domains are thought to help regulate the activity of the HOXB13 protein by controlling the binding of the homeodomain with DNA.
At least two mutations in the HOXB13 gene have been associated with an increased risk of prostate cancer; the disease may also be more aggressive in affected men with a HOXB13 mutation. These mutations are present in every cell of the body and can be passed from one generation to the next. As a result, they are associated with cancers that cluster in families. However, not everyone who inherits a mutation in the HOXB13 gene will ultimately develop prostate cancer. Other genetic, environmental, and lifestyle factors also contribute to a person's cancer risk.
The HOXB13 gene mutations that are associated with prostate cancer alter the MEIS interacting domains of the HOXB13 protein. Researchers suggest that the changes may impair the ability of these domains to regulate the HOXB13 protein's interactions with DNA. As a result, the protein's tumor suppressor function is impaired, resulting in the uncontrolled cell proliferation that can lead to prostate cancer.
- homeobox protein Hox-B13