GSTP1 and breast cancer: McCullough et al. [44] showed that higher self-reported postmenopausal RPA levels were associated with ER + PR + tumours when GSTP1 was methylated, possibly due to its role in detoxification reactions, contrasting to the systematic response to PA that increases the production of reactive oxygen species (ROS)—potentially showing an increased risk of BC due to postmenopausal RPA in ER + PR + breast tumours [44,65].