The first observational study conducted by Coyle et al. [62] in 106 healthy females investigated the effects of self-reported PA on methylation of the promoters of the tumor suppressor genes adenomatous polyposis coli (APC) and ras association domain family member 1 (RASSF1A), an epigenetic alteration commonly associated with breast cancer risk. This evidence concerns the gene APC and breast carcinoma.