[Study on chemosensitivity of colony forming cells]

We suspect a difference between the effective rate of human tumor clonogenic assay (HTCA) and that of clinical chemotherapy against renal cell carcinoma. We investigated the sensitivity of ACHN, the cell line of renal cell carcinoma, and its colony forming cells (dividing cells) obtained on double soft agar against vincristine sulphate (VCR). In addition, PC-3, a cell line of prostatic carcinoma, and HeLa, cell line of cervicar carcinoma, were investigated. We obtained the results that each colony forming cells had higher sensitivity than each parent cells against VCR in the growth activities and the DNA synthesis measured by the uptake of 3H-thymidine. Because the cells targeted by HTCA are dividing cells, they are oversensitive compared with the true sensitivity of tumors.