ESR1 and neoplasm: After the initial tumor was palpated in the Col1a1FRT-STOP-FRT-Cre-ER-T2; KrasFRT-STOP-FRT-G12D/+; p53FRT/FRT; Rosa26mTmG/+ mice, a single dose of 75 mg tamoxifen/kg body weight in corn oil was delivered via intraperitoneal injection.