Melanoma susceptibility: an update on genetic and epigenetic findings

Malignant melanoma is one of the most highly ranked cancers in terms of years of life lost. Hereditary melanoma with its increased familial susceptibility is thought to affect up to 12% of all melanoma patients. In the past, only a few high-penetrance genes associated with familial melanoma, such as CDKN2A and CDK4, have been clinically tested. However, findings now indicate that melanoma is a cancer most likely to develop not only due to high-penetrance variants but also due to polygenic inheritance patterns, leaving no clear division between the hereditary and sporadic development of malignant melanoma. Various pathogenic low-penetrance variants were recently discovered through genome-wide association studies, and are now translated into polygenic risk scores. These can show superior sensitivity rates for the prediction of melanoma susceptibility and related mixed cancer syndromes than risk scores based on phenotypic traits of the patients, with odds ratios of up to 5.7 for patients in risk groups. In addition to describing genetic findings, we also review the first results of epigenetic research showing constitutional methylation changes that alter the susceptibility to cutaneous melanoma and its risk factors.

Hereditary melanoma: Update on syndromes and management: Genetics of familial atypical multiple mole melanoma syndrome

Malignant melanoma is considered the most lethal skin cancer if it is not detected and treated during its early stages. About 10% of melanoma patients report a family history of melanoma; however, individuals with features of true hereditary melanoma (ie, unilateral lineage, multigenerational, multiple primary lesions, and early onset of disease) are in fact quite rare. Although many new loci have been implicated in hereditary melanoma, CDKN2A mutations remain the most common. Familial melanoma in the presence of multiple atypical nevi should raise suspicion for a germline CDKN2A mutation. These patients have a high risk of developing multiple primary melanomas and internal organ malignancies, especially pancreatic cancer; therefore, a multidisciplinary approach is necessary in many cases. The value of dermoscopic examination and total body photography performed at regular intervals has been suggested by a number of studies, and should therefore be considered for these patients and their first-degree relatives. In addition, genetic counseling with the possibility of testing can be a valuable adjunct for familial melanoma patients. This must be performed with care, however, and only by qualified individuals trained in cancer risk analysis.

Hereditary melanoma: Update on syndromes and management: Emerging melanoma cancer complexes and genetic counseling

Recent advances in cancer genomics have enabled the discovery of many cancer-predisposing genes that are being used to classify new familial melanoma/cancer syndromes. In addition to CDKN2A and CDK4, germline variants in TERT, MITF, and BAP1 have been added to the list of genes harboring melanoma-predisposing mutations. These newer entities may have escaped earlier description in part because of more advanced technologies now being used and in part because of their mixed cancer phenotype as opposed to a melanoma-focused syndrome. Dermatologists should be aware of (and be able to recognize) the clinical signs in high-risk patients in different contexts. Personal and family histories of cancer should always be sought in patients with multiple nevi or a positive history for melanoma, and should be updated annually. Various features that are unique to specific disorders, such as the appearance of melanocytic BAP1-mutated atypical intradermal tumors in cases of BAP1 melanoma syndrome, should also be recognized early. These patients should be offered regular screenings with the use of dermoscopy and total body photography, as needed. More importantly, referral to other specialists may be needed if a risk for internal malignancy is suspected. It is important to have in mind that these patients tend to develop multiple melanomas, along with various internal organ malignancies, often at younger ages; a multidisciplinary approach to their cancer screening and treatment is ideal.