Fluorescence in situ hybridization as a tool in molecular diagnostics of melanoma

Structural and numerical chromosomal abnormalities have been observed in all types of malignancies. These events are associated with neoplastic pathogenesis and progression (1). For a long time, conventional cytogenetics analysis was the prevalent approach in assessing chromosomal rearrangements. Many data were collected initially from hematologic malignancies because of ease of analysis, despite the fact that they represent only 10% of all malignancies (2). Cytogenetic data on solid tumors were hampered by the technical difficulties in obtaining dividing malignant cells. During the last two decades, these problems were solved and data have been quickly acquired. Karyotyping of malignant melanoma cell lines reveals more than 95% of the cases presenting aneuploidy (numerical chromosome abnormalities: near triploidy) (3), and all the cell lines present structural abnormalities (balanced and unbalanced translocations, inversions and deletions) (see, e.g., German Collection of Microorganisms and Cell Cultures [Dr. H. Drexler] at http://www.dsmz.de (4,5). Cytogenetic analysis of malignant melanoma cells allowed the identification of nonrandom karyotypic changes involving chromosomes 1, 6, and 7 and, to some extent, chromosomes 9 and 10.