A new human breast carcinoma cell line (PMC42) with stem cell characteristics. I. Morphologic characterization.

A new human breast carcinoma cell line (PMC42) was established from a pleural effusion from a woman with metastatic breast cancer. The cells were significantly pleomorphic even after 3.5 years in continuous culture. Eight different cell types could be characterized morphologically in monolayer culture. Cells cloned in agar and replated in monolayer culture were equally heterogenous. Cells also grew in suspension in papillary clusters that structurally resembled glandular organoids. Electron microscopy confirmed the differentiated structure of these cells in which many of the features of lactating breast tissue were evident. It is proposed that this is a culture derived from a malignant breast stem that has retained its ability to differentiate in vitro.