Reversibility of hydrocortisone-effected regression of induced skin carcinomas in mice.

In 1953 it was demonstrated by EngelbrethHolm and Asboe-Hansen (3) that intraperitoneal injection of cortisone markedly inhibits the devel opment of skin tumors and prolongs the latent period in ST/Eh mice painted once on the dorsum with 9,10-dimethyl-l,2-benzanthracene. In further experiments by Zachariae and AsboeHansen (4), hydrocortisone (17-hydroxycorticosterone) acetate, injected topically into the con nective tissue of fully developed precancerous skin papillomas induced as stated above, resulted in complete regression in 95 per cent of the males. In a control group of males injected with an isotonic saline solution, 48 per cent were tumorfree after 7 weeks' treatment. The corresponding