Effect of persistent organochlorines on (a) pS2 mRNA expression in MCF-7 and (b) p21Waf1/Cip1 in MCF-7(BUS). The pS2 data are normalized to GADPH and the related to solvent control (set to 1). Dark bars indicate cotreatment of 17β-estradiol and the given compound. *
P < 0.05 compared with solvent-treated cells, **
P < 0.05 compared with 17β-estradiol (10 nM)-exposed cells. Data are presented as mean ± standard deviation of at least three independent experiments (pS2) or two independent experiments assayed in duplicate (p21Waf1/Cip1). E2, 17β-estradiol; Tox.Tech., toxaphene (technical mixture); TCDD, 2,3,7,8 tetrachlorodibenzo-p-dioxin; PCB, polychlorinated biphenyl; EtOH, ethanol; DMSO, dimethyl sulfoxide.