PGR and breast cancer: Hence, the fact that we see a substantial overlap of PR-BSs in cervical samples from women with breast cancer and in normal breast tissue from women with a BRCA mutation is perfectly aligned with the view that overall higher (lifetime) levels of progesterone in women at risk lead to a reduction of methylation in both surrogate (i.e. cervical) and at-risk (i.e. breast tissue and here likely cells like luminal mature cells) which eventually triggers breast cancer (Fig. 6e).