Invasive breast carcinoma occurring in young women (defined as ages 35–40 years or younger) generally has a higher proportion of pathological features associated with more aggressive disease (Higher proportion of late stage, positive nodes, high grade, extensive intraductal component, presence of lymphatic/vascular invasion, absence of estrogen receptor, amplification or over expression of Her2/neu gene, higher S-phase fraction) compared to breast carcinoma occurring in older patients [9,16-21]. Here, ESR1 is linked to breast carcinoma.