Fig. 3.

Cumulative and interactive effects from sex chromosomes, sex hormones, and the sex epigenome result in sexual dimorphism in BC. Sex-specific differences in post-translational modifications and chromatin organizations, also known as the sex epigenome, functionally influence gene expression and/or response to the environment. We propose a novel framework to understand the drivers of sex differences in BC: the sex epigenome acts as a universal platform where the effects of sex chromosomes and sex hormones converge to result in the observed sex bias in BC.