Parabens enable suspension growth of MCF-10A immortalized, non-transformed human breast epithelial cells

ABSTRACT Parabens (alkyl esters of p‐hydroxybenzoic acid) are used extensively as preservatives in consumer products, and intact esters have been measured in several human tissues. Concerns of a potential link between parabens and breast cancer have been raised, but mechanistic studies have centred on their oestrogenic activity and little attention has been paid to any carcinogenic properties. In the present study, we report that parabens can induce anchorage‐independent growth of MCF‐10A immortalized but non‐transformed human breast epithelial cells, a property closely related to transformation and a predictor of tumour growth in vivo. In semi‐solid methocel suspension culture, MCF‐10A cells produced very few colonies and only of a small size but the addition of 5 × 10‐4 M methylparaben, 10–5 M n‐propylparaben or 10–5 M n‐butylparaben resulted in a greater number of colonies per dish (P