To determine effects of phytoestrogens, naringenin, resveratrol, or quercetin on initial tumor growth and TICs within the bulk tumor, an ER+ PDX tumor (BCM-5097) was implanted subcutaneously in female, athymic nude, ovariectomized mice and treated with a vehicle (no E2), E2, naringenin, resveratrol, or quercetin for 2 weeks. The gene discussed is ESR1; the disease is neoplasm.