SHORT-TERM PRIMARY CULTURE OF EPITHELIAL-CELLS DERIVED FROM HUMAN BREAST-TUMORS

As experimental models for breast cancer, most studies rely on establi shed human breast cancer cell lines. However, many of these lines were established over 20 years ago, many from pleural effusions rather tha n the primary tumour, so the validity of using them as representative models is questionable. This paper describes our experiences, over a 3 -year period, in establishing short-term epithelial-cell-enriched prep arations from primary breast tumours based on differential centrifugat ion followed by culture in selective media. Epithelial cells were succ essfully cultured from 55% of samples, but culture success did not app ear to be correlated with tumour histology, stage, grade or node statu s. Epithelial cell-enriched cultures were immunopositive for broad-spe ctrum cytokeratin and epithelial membrane antigen (EMA). Positivity fo r keratin 19 confirmed that the cultures contained tumour-derived cell s, which additionally showed significantly higher activity of the redu ctive pathway of the steroid-converting enzyme 17 beta-hydroxysteroid dehydrogenase type I. That the cultures contained tumour and not norma l epithelial cells was further substantiated by the complete absence o f the calmodulin-like gene NB-l in tumour-derived cultures; this is on ly associated with normal breast epithelia. Eighty-five per cent of cu ltures established from oestrogen receptor (ER)-positive tumours expre ssed ER in vitro; this was functional in 66% of cultures, although ER- positive phenotype was gradually lost over time. In conclusion, epithe lial cells can be isolated and maintained as short-term cultures from primary breast tumours irrespective of histopathological or clinical d etails, providing a model system with a greater biological and clinica l relevance than breast cancer cell lines.