Binding of the chemokine CXCL12 to its receptors CXCR4 and CXCR7 is positively associated with the progression of breast cancer; high expression of both CXCR4/CXCR7 has been implicated in the activation of EMT, tumor stemness, and chemoresistance [26]. The gene discussed is ACKR3; the disease is neoplasm.