Oxybenzone alters Esr1 and PR in the mammary gland. (A) Expression of Esr1, the gene encoding ERα, in the mammary gland reveals an intermediate phenotype for all three treated groups. (B) Mammary gland sample after an immunohistochemistry for ERα expression. Original scale bars, 20 µm; red arrows indicate positive cells. (C) Quantification of ERα expression in mammary gland samples reveals no effects of parity or oxybenzone treatment. (D) mRNA expression of PR (total) in the mammary gland reveals no differences among treatment groups. (E) Immunohistochemistry for PR. Original scale bars, 20 µm; red arrows indicate positive cells. (F) Quantification of PR expression in mammary tissue reveals an intermediate phenotype in the oxybenzone-95P and oxybenzone-NOAEL treatment groups. In all panels, different letters indicate significant differences among groups, P < 0.05, Fisher LSD post hoc after significant ANOVA.