Differences in chromosomal aberrations between nodular and superficial spreading malignant melanoma detected by interphase cytogenetics.

At present, little information is available on specific chromosomal aberrations in malignant melanomas of different subtypes and different growth behaviors. Therefore, we have applied fluorescence in situ hybridization on isolated interphase cells from paraffin sections of 79 primary tumors of malignant melanomas: 47 nodular melanomas and 32 superficial spreading melanomas in various stages. We used centromeric probes for the chromosomes 1, 4, 6, 7, 9, 10, 11, 12, 15, 17, 18, X, and Y and a midisatellite probe localized in 1p36. The number of chromosomal aberrations and the ploidy of the cells rose with the tumor stage in both subtypes, although in superficial spreading melanomas, fewer chromosomal abnormalities were detectable than in nodular melanomas. A deletion in 1p36 could only be found in nodular melanomas (mostly in higher tumor stages), not in superficial spreading melanomas. Our results show that the different histologic subtypes of malignant melanoma of the skin differ also in their chromosomal aberrations. In addition, it seems that there may be a correlation between the growth characteristics and putative tumor suppressor genes on 1p36.