Cytogenetic studies of human malignant melanoma cell lines.

Cytogenetic studies were performed on six cell lines derived from three patients suffering from malignant melanomas. The modal chromosome numbers were in the hypotriploid to hypertetraploid ranges and both the numerical and structural aberrations of chromosomes were found. Aberrations were most frequently observed in chromosomes 1, 6 and 7. Deletion of 1q was consistently present in all cell lines, while loss of 6q was observed in two cell lines of case 1. Translocations t (Y; 6) and t (6;?) occurred in one cell line from case 3. An increased number of copies of chromosome 7 was a characteristic feature of the cell lines from case 2. Since positive correlation between the expression of EGF receptors and an increased dosage of chromosome 7 has been reported for malignant melanomas and the gene for EGFR has been mapped to band 7p12-p13, this phenomenon might be of importance for the proliferation of malignant melanoma. The findings of the present study are generally in agreement with the data previously published in the literature, indicating the existence of specific non-random chromosome lesions during melanoma development.