ESR1 and neoplasm: Finally, after the initial tumor was palpated in the lower limb in a Col1a1FRT-STOP-FRT-Cre-ER-T2; KrasFRT-STOP-FRT-G12D/+; p53FRT/FRT; Rosa26mTmG/+ mouse, one dose of 2 mg 4-hydroxytamoxifen in PBS was delivered via intraperitoneal injection.