GROWTH-RATES OF NORMAL AND ABNORMAL HUMAN MAMMARY EPITHELIA IN CELL-CULTURE

Abstract

The in vitro growth rates of different classifications of human mammary epithelium were compared. Samples included 4 established breast cell lines and excised tissue or breast fluid cells originating from 40 women and comprising 3 classifications: normal, nonmalignant atypical and malignant. Growth was quantitated in situ and expressed as population doubling time. Malignant cells divided at a slower mean rate than normal cells. Population doubling time values of malignant cells were more heterogenous than those of normal cells. Cultures from nonmalignant atypias showed population doubling time means and SDs between those of normal and malignant cells. Long-term mammary tumor cell lines divided more slowly than normal cells. Discussion includes implications of data for the preneoplastic state and cell culture of mammary epithelium.