Testing the chemosensitivity of renal carcinoma in vitro

Tumour cells from 23 renal carcinomas were exposed in vitro to increasing concentrations of medroxyprogesterone acetate (MPA) or one of several cytotoxic agents. Thereafter the uptake of 75Selenomethionine (75SeM) was compared to that of tumour cells not exposed to the drug. Using drug concentrations similar to those seen following in vivo administration in patients, MPA produced greater than or equal to 50% inhibition of 75SeM uptake in 5 of 23 cases. The comparable proportion for doxorubicin was 4 of 5 and for mitozantrone 7 of 12. Methotrexate and Vinblastine were much less effective. In all cases where greater than or equal to 50% inhibition was obtained with doxorubicin and mitozantrone the carcinoma had spread beyond the kidney. Thus drug sensitivity may be associated with a high mitotic rate.