Soft agar colony formation assay for in vitro chemotherapy sensitivity testing of human renal cell carcinoma: Mayo Clinic experience.

Two hundred six different samples of human renal carcinoma were tested for in vitro chemotherapy sensitivity using a soft agar colony formation assay similar to that originally described by Salmon and colleagues. Eighty of 159 (50 per cent) evaluable tumor tests showed colony formation in vitro and gave clinical drug sensitivity information. Two-thirds of tumors were resistant to all drugs tested, despite a median number of drugs tested per tumor of 14.5. Five tumors (6 per cent) were remarkably sensitive to numerous anticancer drugs in vitro. The most active drugs found in vitro were teniposide, actinomycin D, bleomycin, hydroxyurea, mitoguanazone dihydrochloride, mitomycin C and L-alanosine. Fourteen other drugs tested showed low in vitro cytotoxicity.