[Evaluation of chemosensitivities of human breast cancers by primary culture assay in vitro].

Chemosensitivities of 32 human breast cancer to 6 antitumor drugs were assayed in vitro using MTT colorimetric method. The results showed that the chemosensitivity of primary breast cancer cultures varied remarkably from one patient, and from one drug, to another with hundred-to thousand-fold differences. The distribution of 50% inhibition concentration (IC50) was significantly deviated from normal distribution (P < 0.0001), and the drug sensitivity could be divided into four different catagories by means of percentile method. Preliminary results showed that the in vitro chemosensitivities of different antitumor drugs were consistent with the clinical therapeutic responses It seems that the herein reported assay might be useful on an individual basis to optimize chemotherapy of human breast cancer.