核 DNA 量による乳癌の悪性度判定ならびに内分泌療法の作用機序の研究―Flow cytometry による解析―

To evaluate for primary breast cancer, flow cytometric DNA analysis has been performed on 105 paraffin-embedded tissues. The S-phase fraction and proliferation index correlated significantly with clincopathological factors, sunh as n-number, tumor size, histological stage and hormone receptors. However, there was no correlation between the level of ploidy and the clinicopathological factors. DNA analysis using flow cytometry was found to be useful for the estimation of prognosis and evaluation of malignancy of breast cancer. The effect of medroxyprogesterone acetate (MPA) on primary breast cancer cell kinetics was investigated by flow cytometry. Nuclear DNA contents were measured in 67 cases. MPA, 1,200mg/day, was orally administered for two weeks in 12 cases (MPA group) and the remain-ing cases (n-MPA group) served as the controls, until the day before operatopn. The DNA histograms were compared between both groups. The mean percentage of G0 + G1 phase was higher and that of S-phase and G2 + M phase, lower, in the MPA group than in the n-MPA group. Especially in estorogen receptor-positive and premenopausal cases, significant differ-ences were present between both groups. These results suggest that MPA could inhibit DNA synthesis with a delay of the cell cycle progression in human breast cancer.