Date Due: January 30, 2015
Unit 4 Case Study 2: Skin Cancer
What genetic mutations produce the greatest risk of skin cancer?
An alteration in the gene BRAF has been known to cause many melanomas. Researchers have found the gene in about half of all melanoma cases. It is known as a switch gene because a slight mutation can cause it to turn on abnormally; it will then lead to uncontrolled cellular growth and cancer. The mutations most commonly seen in familial melanoma occur in another gene known as p53. When p53 is in its normal state, it functions as a tumor suppressor. It does this by giving damaged cells the chance to repair themselves without progressing to cancer, but if it is altered it can produce cancer. It has also been found that ultraviolet damage can damage the p53 gene, altering its ability to suppress tumors. CDKN2A (cyclin-dependent kinase inhibitor 2A) gene has also been known to cause familial cancer (Melanoma Causes and Risk Factors).
What genes control the color of skin, hair, and eyes?
Melanocortin 1 receptor (alpha melanocyte stimulating hormone receptor) or MC1R is the gene responsible for the color of our hair skin and nails. This receptor plays an important role in normal pigmentation. The receptor is primarily located on the surface of melanocytes. Melanocytes are specialized cells that produce a pigment called melanin. Melanin is the substance that gives skin, hair, and eyes their color. Melanocytes make two forms of melanin, eumelanin and pheomelanin. The melanocortin 1 receptor controls which type of melanin is produced by melanocytes. The receptor triggers a series of chemical reactions inside melanocytes that stimulate these cells to make eumelanin. If the receptor is not activated or is blocked, melanocytes make pheomelanin instead of eumelanin. Eumelanin is known to protect the skin from damage caused by ultraviolet radiation in sunlight (MC1R, 2015).
Are these gene mutations germ-line (passed from parent to child), or caused by exposure to UV light?
Heredity plays a major role in melanoma. About one in every 10 patients diagnosed with the disease has a family member with a history of melanoma. If your mother, father, siblings or children have had a melanoma, you are in a melanoma-prone family, and have a 50 percent higher chance of getting melanoma, than those who do not. It has also been found that people who spend time in the sun at an early age and later in life are at a greater risk for melanoma (Melanoma Causes and Risk Factors).
What recommendations about UV light exposure would be made to individuals who are genetically susceptible to skin cancer?
Avoid intense intermittent exposure to UV radiation, both solar and non-solar (tanning beds). Try to stay in the shade, especially between 10 AM and 4 PM. If you are out in the sun it is very important to avoid getting a sun burn. Try to limit the amount of time spent in the sun to ensure this doesn’t happen. Tanning beds have