Cytogenetic analysis of melanoma cell lines: subclone selection in long-term melanoma cell cultures.

We employed G-banding cytogenetic analysis to follow the clonal constitution of short-term cultures of metastatic malignant melanoma compared to their long-term cultures. Eight metastatic melanoma cell lines were analyzed. No long-term culture was found to be identical to its line of origin. In all cultures there was a selection of one subclone and emergence of its own subclones. In the majority of cultured tumors (5/8), this process was associated with a decrease in the number of subclones composing the line. We suggest that subclone selection in long-term tumor cultures can be associated with a change in phenotype. Therefore, caution is required when employing long-term cultures for research and therapy.