ESR1 and neoplasm: Namely, it elicits markedly reduced tumor volume and wet weight of human A549 lung tumors grown in the flank [5, 26]; of orthotopic human breast tumors positive for the estrogen receptor (BT-474 or ZR-75-1) and over-expressed HER2 (BT-474) in the mammary fat pad [27]; of human LNCaP prostate cancer xenografts [28] as compared to tumors from control animals [3].