Detection of three novel translocations and specific common chromosomal break sites in malignant melanoma by spectral karyotyping

Chromosomal aberrations in malignant melanoma cells have been reported using standard chromosome banding analysis and comparative genomic hybridization. To identify marker chromosomes and translocations that are difficult to characterize by standard banding analysis, 15 early passage malignant melanoma cell lines were examined using spectral karyotyping. All 15 tumor cell lines had lost all or part of 1p and 10q. Losses of material on chromosome arms 4p (12/15), 6q (12/15), 9p (15/15), 12p (13/15), 12q (13/15), 13q (11/15), and 19q (14/15) were the next most frequent events. Gain of chromosome arms 1q (11/15), 6p (13/15), and 20q11 (14/15) was also observed. Interestingly, we identified translocations der(12)t(12;20)(q15;q11), der(19)t(10;19)(q23;q13), and der(12)t(12;19)(q13;q13) in 4/15 tumors. Three recurring translocations involving four of the most frequent break points were detected. The identification of recurring translocations and unique chromosome break points in melanoma will aid in the identification of the genes that are important in the neoplastic process.