Selective Cell Culture of Primary Breast Carcinoma1

We have used culture conditions which simulate the microenvironment of breast tumors for the isolation and propagation of primary breast tumor cells in vitro. In this monolayer setup, the mixture of cells dissoci ated from primary breast tumors is subjected to self-created gradients of oxygen and nutrients as well as metabolic waste and extracellular pH. The tumor populations isolated under these novel conditions have displayed phenotypic properties characteristic of breast carcinomas, including ho mogeneous expression of cytokeratin 19, and increased mitochondrial retention of the cationic dye rhodamine 123. Nonmalignant cultures from reduction mammoplasty were unable to survive these conditions. One tumor population which reached passage 10 was aneuploid for chromo somes 15 and 17, and displayed a p53 mutation in exon 8. These studies strongly suggest that the culture conditions described here can suppress the growth of normal breast cells, thereby allowing selective isolation of some populations of slow-growing primary tumor cells in vitro.