Cytogenetics of melanoma: a review

Malignant melanoma is an aggressive cutaneous neoplasm whose incidence has continued to increase worldwide. Currently, histopathologic examination of specimens is the gold standard for the diagnosis and categorization of melanoma. Cytogenetic analysis represents a powerful, and currently underused, adjunct to traditional histologic examination in distinguishing nevi and melanomas. Chromosomal studies have shown that malignant melanomas often contain multiple chromosomal alterations, most commonly of chromosomes 1, 6, 7, 9, 10 and 11. These chromosomes often include genes within the MAPK molecular pathway, which is involved in the development and progression of melanoma. Fluorescence in situ hybridization (FISH) can detect a number of recurrent anomalies, and commercially available kits for melanoma detection have been devised. The utility of cytogenetics in melanocytic lesions at certain anatomic sites has been evaluated, including acral lesions, uveal lesions, and lymph node metastases. Recurring cytogenetic anomalies have been defined in various challenging histologic subtypes, such as desmoplastic melanomas and Spitzoid lesions. Cytogenetic analysis may also be used to provide supplementary information in prognostication, particularly in uveal melanomas. We provide a brief review of the molecular pathways found in melanoma and a summary of what is known and remains unknown regarding cytogenetic aberrations associated with malignant melanoma.