p,p'-DDE increases the proliferation of CAMA-1 cells in the presence of 17β-estradiol (E2) and dihydrotestosterone (DHT). E2 was added at a concentration of 100 pM, and DHT was added at concentrations of 100 pM (a), 500 pM (b), or 1,000 pM (c). p,p'-DDE alone has little impact on CAMA-1 proliferation (d). Cell proliferation was assessed after 9 days of treatment. Each bar represents the mean ± standard error of the mean of four independent experiments. Double asterisk indicates P < 0.01 versus E2+DHT treatment and †† indicates P < 0.01 versus 0.1 μM p,p'-DDE as determined by an analysis of variance followed by a one-tail Bonferroni post hoc test. p,p'-DDE, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene.