CELL-PROLIFERATION MEASURED BY MIB1 AND TIMING OF SURGERY FOR BREAST-CANCER

We have investigated the use of the antibody MIB1 as a proliferative a nd prognostic marker in breast cancer and whether changes in prolifera tive activity could account for differences in prognosis of premenopau sal women operated on during different phases of the menstrual cycle. MIB1 expression was strongly correlated with S-phase fraction and hist ological grade. There was no difference in MIB1 scores between differe nt phases of the menstrual cycle. Both MIB1 score and timing of surger y correlated significantly with duration of survival, while the two to gether were even stronger predictors of overall survival. Women with s lowly proliferating tumours surgically removed in the luteal phase had a very good prognosis, whereas women with rapidly proliferating tumou rs excised at other times of the cycle had a worse prognosis.