A rapid in vitro method for measuring cell proliferation in human breast cancer.

A method has been developed for studying in vitro the cell proliferation kinetics of human breast cancer, Surgical specimens from primary tumors were studied in 56 patients. Viable cell suspensions for assay were obtained by the dissociation of tumor tissue with collagenase. Mean Labeling indices of 2.43 +/- S.D 2.05 and 4.48 +/- S.D. 3.73, respectiviely, were found after incubation with 3HTdR for 2 hours and 24 hours. Mean S-times of 21.9 +/- S.D. 4.3 hours were estimated by 3H and 14C-TdR double-labeling. The kinetic data have been validated by parallel labeling studies in vivo and in vitro in four patients. The processing of autoradiographs using gold latensification provided slides for kinetic analysis within 3 days. The assay offers a method that is useful in the planning and monitoring of drug therapy.