An immunocytochemical and ultrastructural study of heterogeneity in the human breast carcinoma cell line PMC42.

A recently established human breast carcinoma cell line has been reported to exhibit a number of morphological cell types in monolayer cultures as defined by phase-contrast microscopy. The cell line also produces cords of viable cells floating within the culture medium. Cultures of this cell line, grown in monolayer, on collagen gels, and as floating cords of cells, were studied by transmission electron microscopy and immunocytochemistry. A detailed analysis of the staining pattern obtained with a series of monoclonal antibodies with well-defined human breast epithelial cell specificities and a polyclonal antikeratin antibody showed PMC42 to resemble cultures of both normal human breast and other human breast carcinoma cell lines. The pleomorphic nature of PMC42 cultures was confirmed at an ultrastructural level, and of the eight cell types observed by phase-contrast appearance, seven ultrastructural counterparts were observed. In addition, the presence of intracytoplasmic lumina and overt epithelial differentiation confirm a breast epithelial origin for this cell line.