In mice implanted with HR+ breast tumors, estradiol also augmented CCL2 levels both in serum and in tumor itself, and blocking CCR2 by RS102895 significantly slowed estrogen-stimulated tumor growth and inhibited liver metastasis largely on account of decreased proliferative activity in tumor cells and reduced angiogenesis and macrophage infiltration in tumor stroma. The gene discussed is CCL2; the disease is neoplasm.