Karyotypic changes with neoplastic conversion in morphologically transformed golden hamster embryo cells induced by X-rays.

Chromosomes from nine morphologically transformed (MT) cell lines (designated MT14 to MT22) of Golden hamster embryo cells induced by X-rays and from tumor-derived cell lines (MT14T to MT22T), obtained after injection of MT cells, were analyzed by the Giemsa banding method. MT cell lines showed a variety of numerical abnormalities. All of the MT cell lines involved trisomy of chromosomes 11 (80 to 100% of cells in each cell line) and 3 (8% of MT22 cells and 100% in other cell lines). Although the latent period for tumor growth differed greatly, eight of nine MT cell lines (MT14 to MT21) produced tumors at the site of injection. All tumor-derived cell lines involved trisomy of chromosome 3 at a 100% rate of incidence. Seven of nine tumor-derived cell lines (MT15T to MT18T, MT20T to MT22T) lost one chromosome 11 from the trisomic condition, resulting in disomy of chromosome 11. These results suggest that trisomies of chromosomes 11 and 3 may play a role in X-ray-induced neoplastic progression.