CCR2 and breast neoplasm: In our study, we provide evidence to three novel observations: (1) persistent stimulation of MSCs by inflammatory cytokines induces MSC-to-CAF conversion; (2) persistent stimulation by inflammatory cytokines has a much more robust impact on the MSCs than short-term cytokine stimulation and leads to the generation of inflammatory CAFs; and (3) factors that are released by inflammation-driven CAFs promote the migratory abilities of luminal-A breast tumor cells by inducing the activation of Ras-activating receptors, together with the chemokine receptors CCR2, CCR5, and CXCR1/2.