Neoplastic transformation of hamster embryo cells irradiated in utero and assayed in vitro

Pregnant hamsters were exposed to 300 rad of x rays at 12 days of gestation and the embryos were removed 30 min later. Cell cultures were prepared and transformed cells were identified by altered morphology and growth patterns. Observations were made on chromosome number, fibrinolytic activity of transformed cells, release of macrophage inhibitory factor, the pattern of cellular lysosomal hydrolases, and the ganglioside content of cells. The transformed cells gave rise to tumors in syngeneic hamsters