CHARACTERIZATION OF 4 MELANOMA CELL-LINES WITH ELECTRON-MICROSCOPY, IMMUNOCYTOCHEMISTRY, CYTOGENETICS, FLOW-CYTOMETRY, AND SOUTHERN ANALYSIS

Four cell lines established from human metastatic malignant melanoma, derived from four patients, were analyzed. Ultrastructurally and immunocytochemically, the cultured tumor cells had retained characteristic features of melanocytes and of the primary malignant melanomas. The genetic stability was investigated by repeated flow-cytometric and cytogenetic analyses over 24 months of continuous cultivation. The DNA indices ranged from 1.7 to 2.1 and were stable during the entire period. The same was true for the karyotypes, which had modal numbers ranging from 50 to 84. The most common types of abnormalities were: isochromosomes i[1q], i[9q], translocations [1;17] and [3;6], and other aberrations [1p+,4p+, 5p+, 11p+, 11q-, 11q+]. Abnormalities involving chromosome 1 were present in all cell lines, but loss of genetic material from chromosome lp was demonstrated in only one of four cell lines when tested by the Southern blotting technique using a lambdaMS1 probe.