X-ray induced in vitro neoplastic transformation of human diploid cells.

Techniques have recently been developed to identify and score quantitatively neoplastic transformation caused by X rays in cultured cells derived from rodents. Because of their relevance to estimates of human cancer risk, it is clearly desirable to carry out similar experiments with cultured cells of human origin. The present report describes for the first time the neoplastic transformation in vitro of human diploid cells by X-ray irradiation into cells which can progress in vitro into advanced stages of neoplastic development, namely, to form colonies in agar and give rise to tumours when injected into nude mice.