Soft agar clonogenic assay for primary human renal carcinoma: in vitro chemotherapeutic drug sensitivity testing.

Dispersed tumor cells from primary human renal adenocarcinomas showed typical clonogenic growth in soft agar in seven of 31 instances. In vitro chemotherapy sensitivity testing was performed successfully for five of the seven clonogenic tumors. Extensive inherent resistance to the cytotoxic effects of many standard and experimental chemotherapeutic agents were observed. Occasionally, a single drug showed marked cytotoxicity. Similar results were obtained with soft agar clonogenic chemotherapeutic drug sensitivity assays performed on cells from human renal carcinoma xenografts. These in vitro results agree with clinical experience in the chemotherapy of advanced renal carcinoma. It remains to be determined if the sensitivity or resistance to chemotherapeutic drugs of human renal carcinomas noted in vitro reflects the characteristics of the tumors in vivo. Our results show that it is feasible to evaluate the soft agar assay as a method for selecting drugs for individual patients with renal carcinoma, a disease for which no chemotherapeutic treatment can be recommended at present.