Melanoma and genetics.

As the incidence of malignant melanoma continues to increase and with the completion of the sequencing of the human genome, there have been increasing efforts to identify the "melanoma gene(s)." Although some patients and families have significantly increased risks due to genetic predisposition, most melanoma cases are sporadic and likely result from low to moderate risk genetic factors. This review focuses on the genes that cover the greatest risk of developing melanoma. It is important to remember that many--if not most--cases of melanoma are the result of undiscovered variants. The strongest genetic risk for the development of melanoma results from heritable alterations in cyclin-dependent kinase inhibitor 2A (CDKN2A) gene, which encodes two separate but related proteins, p16/INK4a and p14/ARF. These proteins help regulate cell division and apoptosis, both of which are necessary to maintain cellular homeostasis. Other important genes include CDK4/6 and retinoblastoma (RB1), which encode downstream proteins in the same pathway as p16/INK4a and p14/ARF. Finally, we discuss the relative importance of the melanocortin 1 receptor (MC1R) gene as a moderate risk factor for melanoma. Although great advances have been made in understanding the molecular basis and genetic predisposition of melanoma, many questions still remain to be answered. Someday soon, it will be possible to predict a patient's risk of melanoma by DNA analysis; however, it is important to reconcile our tremendous technologic capabilities with documented clinical utility.