ESR1 and breast cancer: ER+ (MCF-7) and ER- (MDA-MB-231) human breast cancer cells seeded onto a 6-well ultra-low adherent plate were treated with 1 μM TAM after silencing CSNK1G2, and gene-targeting effect was quantified by real-time PCR for CSNK1G2 (Fig 3E and 3F).