Nonrandom chromosome abnormalities in testicular and ovarian germ cell tumor cell lines.

We report the karyotypic analysis of seven testicular and one ovarian germ cell tumor (GCT) cell lines, a number of which have previously been partially investigated. An i(12p) was found in each of the testicular GCT cell lines, while it was absent in the ovarian GCT cell line. Thus, our study extends to cell lines the observation from fresh tumor tissues that i(12p) is a highly nonrandom chromosomal abnormality of testicular GCT. Additional consistent nonrandom abnormalities in the testicular GCT cell lines included the following: del(1)(p22), del(1)(q21), i(1q), del(7)(q11.2), and del(12)(q14). The del(12)(q14) abnormality was identified in five of the cell lines investigated. This observation, together with previous detection of this marker chromosome in fresh tumor specimens by us and others, suggests that loss of genetic material on 12q may represent a primary change associated with malignant transformation of testicular germ cells. As reported in a previous study, a t(15;20)(p11;q11) translocation was identified in the ovarian GCT cell line. Interestingly, it also was seen in one testicular GCT cell line. In addition, a der(15)t(15;20)(p11;q11) marker chromosome was identified in two other testicular GCT cell lines. Thus, this reinvestigation of GCT cell lines has resolved the discrepancy regarding the occurrence of i(12p) in fresh tumors versus established cell lines and identified additional nonrandom abnormalities of potential importance to the development of GCTs.