ESR1 and breast cancer: Low concentrations of C75 (< 5 μg/ml) inhibited E2-enhanced MCF-7 cell growth; moreover, high concentrations of C75 (>5 μg/ml) decreased cell proliferation to below that observed in the absence of E2, strongly suggesting that FASN inhibition-induced hyperactivation of ERα-driven transcriptional activity does not promote cell proliferation but instead induces significant cytostatic and cytotoxic effects in E2-dependent breast cancer cells.