MEASUREMENTS OF CELLULAR PROLIFERATION BY H-3 THYMIDINE-LABELING INDEX AND FLOW-CYTOMETRY IN BREAST-CANCER PATIENTS

In 50 node negative breast cancer patients, tumor S-phase fraction (SP F) was determined by H-3-thymidine labeling index ((HTLI)-H-3) or flow cytometry (FC). Forty-five patients had tumor cell kinetics measured by both techniques. Twenty-three patients were classified as having hi gh proliferative activity and 22 low by (HTLI)-H-3, while 32 as highly proliferating and 13 low proliferating by FC. In 30 patients only, bo th indices agreed on identifying high or low proliferative activity. T hese results suggest the need of more careful attention to standardiza tion and quality control of cell kinetic data before carrying out clin ical trials based on these parameters.