Radiation-Induced Tumors in Transplanted Ovaries

was similar in the two cases, showing a steeply rising branch at doses up to 0.75 Gy followed by a maximum and an elevated plateau up to 4.00 Gy. A higher incidence of tumors in transplanted organs was apparent for doses up to the maximum, which was attributed to castration-induced hormonal imbalance. Specific death rate analysis of mice dying with ovarian tumors showed that in this system radiation acts essentially by decreasing tumor latency. Ovarian tumors were classified in various histological types and their development in time was followed by serial sacrifice. Separate analysis of death rate of animals carrying different tumor classes allowed further resolution of the various components of the tumor induction phenomenon. It was thus possible to show that the overall death rate analysis masks a true effect of induction of granulosa cell tumors in whole-body-irradiated animals. The transplantation technique offers little advantage for the study of radiation induction of ovarian tumor.