Relationship of steroid receptor, cell kinetics, and clinical status in patients with breast cancer.

The fractions of cells in the different phases of the cell cycle were determined by flow cytometry in 70 human breast tumors and six human benign breast tissues. This procedure showed that 44% of the tumors and none of the benign tissues were aneuploid as determined by mixing experiments using normal peripheral blood as a standard for DNA content per nucleus. The mean percent S-phase fraction (% S) values +/- S.D. for benign and malignant tissues were 6.9 +/- 1.6 and 13.7 +/- 6.5, respectively. By our procedure, aneuploid tumors seem to have significantly higher mean % S value than do diploid tumors. Breast cancer tissue which contained steroid receptors had a mean % S value of 11.3, while those tumors which had neither the estrogen nor progesterone receptors had a mean % S value of 17.1 (p less than 0.01). The estrogen receptor status had a better inverse relationship to the cell kinetic data than did the progesterone receptor status. The use of molecular forms of the steroid receptor was of some assistance in improving the inverse relationship between cell kinetics and steroid receptor status. A trend was observed between lack of steroid receptors and higher probability of the tumor being aneuploid. From the limited clinical data, there was no relationship between cell kinetic and aneuploid data with respect to nodal status, metastatic disease, and menopausal status. The possible use of these data is discussed.