In postmenopausal breast cancer patients treated with aromatase inhibitors, sulindac, a non-selective NSAID, reduced breast density, which is a risk factor for breast cancer, and the results implied that PGE2 inhibition by NSAIDs might be important for breast density change or collagen modulation during breast cancer development (Thompson et al., 2021). This evidence concerns the gene CYP19A1 and breast cancer.