We conditioned early (10 days) or late (20 days) differentiated osteoblasts with either (a) hTERT-HME human mammary epithelial CM (negative control), (b) MDA-MB-231 triple-negative breast cancer CM, (c) MDA-MB-231BRMS metastasis-suppressed breast cancer CM, or (d) MCF-7 ER+ luminal breast cancer CM over a period of 21 days [68]. The gene discussed is ESR1; the disease is breast cancer.