PF4 and breast carcinoma: In the current study, by using the OHD4–12, we explicitly proved that the CXCL4–CXCL12 heterodimer was an active species that inhibited the migration of MDA-MB-231 breast cancer cells driven by the CXCL12 chemokine and established the role of CXCL4–CXCL12 heterodimer in MDA-MB-231 breast cancer cell migration.