Abstract
Recent molecular analyses showed marked differences in the genetic make-up of melanomas that depend on the anatomical location and sun-exposure pattern. In particular, acral melanomas showed characteristic chromosomal aberrations and much lower frequency of BRAF mutation when compared to superficial spreading melanomas that mostly arise in intermittent sun-exposed body areas. These results validate the clinicopathological classification of cutaneous melanoma types originally proposed by Clark et al., and further indicate that potential therapeutic targets might vary among melanoma types. Similar analyses examining common melanocytic nevi and Spitz nevi showed virtually no chromosomal aberrations in these benign melanocytic tumors. This is contrasted by frequent and multiple copy number changes in most melanomas, and strongly suggests potential usefulness of genomic profiling by means of comparative genomic hybridization (CGH) or multiplex ligation- dependent probe amplification (MLPA) as adjunctive diagnostic methods in the future. Finally, RT-PCR assays detecting transcripts of melanocyte differentiation antigens such as tyrosinase and MART-1 were introduced in the diagnosis of sentinel lymph nodes, which may provide relevant information for patients' outcome. [Skin Cancer (Japan) 2004; 19: 287-292]
