The strong AQP5 expression was positively correlated with tumor grade in BCs (p<0.001) and was more frequent in ER/PR-negative BCs than positive ones (14.9% vs. 3.3% and 13.1% vs. 4.8%, respectively, both p<0.001), while Her2/neu-positive status was positively correlated with strong expression of AQP5 (p = 0.005). The gene discussed is ESR1; the disease is neoplasm.