DETECTION OF NUMERICAL CHROMOSOMAL-ABERRATIONS IN MALIGNANT MELANOMASUSING FLUORESCENCE IN-SITU HYBRIDIZATION

To evaluate the numerical chromosomal aberration in malignant melanoma , we have applied fluorescence in situ hybridization (FISH) with repet itive DNA probes specific for chromosomes 1, 6, 7, 9, 10, and 17 on 24 fresh malignant melanomas (primary: 14, metastatic: 8). We defined a tumor that had copies with more than 3 spots as chromosomal gain. Chro mosomal copy number gain was found in 40.9% of the cases for chromosom e 7, 27.2% for chromosome 6, 27.2% for chromosome 17, 22.7% for chromo some 9 and 10, and 4.5% for chromosome 1. Monosomy was found in 54.5% of the cases for chromosome 10, 36.5% for chromosome 9, 27.2% for chro mosome 6, 22.7% for chromosome 17, and 18.1% for chromosome 1 and 7. T he most frequent numerical alterations were seen in chromosomes 6, 7, 9 and 10. Gain of chromosome 6 and 7 and/or losses of chromosome 9 and 10 may play an important role in the tumorigenesis and development of malignant melanomas.