Applications of Additional Techniques to Melanocytic Pathology
Within the last 10 years, it has become evident that the traditional histologic classification of melanoma based upon cellular and architectural phenotypes (e.g., acral, superficial spreading, lentigo maligna) correlates with distinct, recurring genetic alterations. Thus, lentigo maligna, typically located in areas of chronic sun exposure, shows genetic abnormalities distinct from those seen in superficial spreading melanomas, which commonly occur on the trunk, and thus have a lesser degree of sun exposure. Molecular techniques such as fluorescent in situ hybridization (FISH), comparative genomic hybridization (CGH), and DNA sequencing methodologies can detect such differences. As an example, CGH indicates that more than 95 % of melanomas show chromosomal copy number aberrations and as many as 80 % of cutaneous melanomas have mutations in BRAF, NRAS, or KIT. This chapter will review the common mutations and the role of these techniques in the diagnosis, prognosis, and treatment of cutaneous melanoma.
KeywordsComparative Genomic Hybridization Cutaneous Melanoma Extracellular Regulate Kinase Increase Copy Number NRAS Mutation