IL6 and breast carcinoma: Recapitulating this osteoblast phenotype in vitro by using MC3T3-E1 osteoblasts and conditioned medium from MDA-MB-231 and MCF-7 breast cancer cells, the authors showed that this subpopulation expressed lower levels of the inflammatory cytokine IL-6 but increased levels of extracellular matrix remodeling proteins including Col1 and MMP3.