Clonal expansion of cells with trisomy of chromosomes 12 and X in an EBV-transformed lymphoblastoid cell line and establishment of a tumorigenic monoclonal cell line (48,XX,+X,+12).

Clonal expansion of cells with a certain abnormal chromosome constitution has been demonstrated in EBV-transformed lymphoblastoid cell lines, and a new monoclonal tumorigenic cell line (48,XX,+X,+12) has been established. Based on these data and our previous hypothesis that predisposition to tumor development could be associated with inherited susceptibility of certain chromosomes and chromosome regions to breakage, we emphasize that cytogenetic analysis of immortalized cell populations established from normal individuals and cancer patients might be of great importance for predicting development of different primary and secondary malignancies.