Figure 2. Malignant transformation induced by endogenous and equine estrogens: MCF-10A cellular transformation induced by estrogens and metabolites was measured as anchorage-independent growth in soft agar after four weeks.

A. Cells were treated with estrogens or metabolites (1 µM) and COMT inhibitor Ro 41-0960 (Ro, 3 µmol) for 4 weeks before transfer to soft agar. Using one-way ANOVA with Dunnett's post test: *** p<0.001; ** p<0.01 versus DMSO control. B. MCF-10A cellular transformation induced by E₁ with or without the CYP450 1B1 inhibitor αNF (3 µM), and a comparison between transformation potency of 2-OHE₁ versus 4-OHE₁ in MCF-10A cells, 1 µM each. Using one-way ANOVA with Dunnett's post test: *** p<0.001; ** p<0.01 versus DMSO control.