Heredity

Heredity

Is melanoma inherited?

While anyone can get melanoma, people from certain families and ethic backgrounds have a higher risk of developing this cancer. A strong genetic predisposition to skin cancer in the general population, independent of skin phenotype, has been most clearly demonstrated for malignant melanoma.3

Patients with greater than 75-100 moles, a family history of melanoma, and clinically atypical moles have a 35-times greater risk of developing melanoma.4 In this same group, the median age for diagnosis also drops from 48 years to 28 years in successive generations.5

People with dysplastic nevi have a six-times greater risk of developing melanoma than those without dysplastic nevi.6 People with fair skin, blue eyes, red hair, easily freckle or of northern European background have the highest risk, but melanoma can arise in any skin type including African Americans and those of Mediterranean descent. It can also appear on non-sun exposed portions of the body.

People who have a primary relative (sibling, parent, child) with melanoma are at greater risk with figures ranging from 1-2% for inherited mutations. Percentages increase with more than one relative diagnosed with melanoma, diagnosis at a young age, and presence of dysplastic nevi. Uncommon genetic syndromes such as xeroderma pigmentosum, albinism, and Giant Nevi Syndrome also predispose one to melanoma.

The genetics of melanoma are complex. Recent research has shown a correlation between UVB radiation damage and subsequent genetic changes. These changes include defects in tumor suppressor genes, defects in DNA repair genes, oncogenes (normal genes that mutate), as well as allelic (pair) changes in chromosomes 9 and 10, and gene rearrangements in 1, 6, 7, and 11.7 In short, sunlight can both damage and inactivate key components of normal cell growth. In a person who has inherited a genetic predisposition to any type of skin cancer, UV radiation will precipitate the process of mutation.

Is melanoma contagious?

Melanoma is not contagious and therefore cannot be spread from person to person by coughing, sneezing, bodily contact, or sexual relations. It does however run in families due to the genetic predisposition and can be acquired by recipients of organ transplants.