With the advent of selective estrogen replacement modulators (SERMs) and aromatase inhibitors, there has been a significant impact on morbidity and mortality in estrogen receptor (ER) positive breast cancer however; these drugs pose a number of serious adverse effects like uterine cancer, thromboembolism, cataracts, and perimenopausal symptoms [1-3]. The gene discussed is ESR1; the disease is uterine cancer.