PhosphorImager images of hybridizations with BRCA1 (7.8 kb), pS2 (500 bp), and GADPH (1.3 kb) probes against the same northern blot membrane with 20 μg/lane total RNA from MCF-7. Concentrations of the chemicals are as shown in Fig. 2. The filter represents only one experiment. The collective data are presented in Figs 2 and 3. After hybridization with BRCA1, the filter was stripped and rehybridized with pS2 and then with GADPH. MDA-MB-231 data are not shown. E2, 17β-estradiol; Tox.Tech., toxaphene (technical mixture); Ici, ICI 182780; TCDD, 2,3,7,8 tetrachlorodibenzo-p-dioxin; PCB, polychlorinated biphenyl; EtOH, ethanol; DMSO, dimethyl sulfoxide.