[In vitro chemosensitivity test by human tumor colony forming assay]

In vitro chemosensitivity of urological cancers was assessed by a human tumor colony forming assay (HTCA) and a 3H-thymidine incorporation assay. Primary tumor cells from 160 of 253 (63%) urological cancers showed adequate colony growth (greater than 30 colonies per well), and there was a 57% true positive and 100% true negative rate for predicting clinical response of anticancer agents. On the other hand, cells from 37 of 45 (82%) urologic cancers incorporated a sufficient amount of 3H-thymidine (greater than 300 cpm). However, when the positive control drug (chromomycin A3 100 micrograms/ml) was used for the assay quality control, the successful assay rate of the HTCA (38%) was lower than that of the 3H-thymidine incorporation assay (75%), while there was a significant correlation in drug sensitivities between the two assays. Thus, the 3H-thymidine incorporation assay seemed to be more useful than the HTCA for evaluating the chemosensitivity of urologic cancers.