BRCA1 and breast cancer: Studies have shown that females who use hormonal replacement therapy (HRT) are at increased risk of breast cancer, and compared with never used, both estrogen-alone therapy and combined estrogen and progesterone therapy are linked to an elevated risk of cancer [7]. Breast cancer develops due to an inherent fault in deoxyribonucleic acid (DNA) and genes like P53, BRCA1, and BRCA2, along with exposure to estrogen, mutations in the genes encoding for the RAS/MEK/ERK pathway, and P13K/AKT pathway protect healthy cells from cell suicide.