Clonal growth of normal and malignant human breast epithelia.

We have developed an efficient method for the growth of colonies from single breast epithelial cells derived from nonmalignant [6], primary [7], and metastatic [1] surgical specimens. The immediate sources of the cells were primary and secondary mass cultures. An enriched culture medium and fibroblast feeder layers were used. A linear relationship between the number of cells cultured and the number of colonies obtained was found. Efficiency of colony formation was higher for those derived from nonmalignant specimens (mean 24%) than those derived from malignant specimens (mean 11%). Fibroblast feeder layers increased the efficiency of colony formation and also supported extended growth of colonies.