PF4 and melanoma: Further interest in CXCL4–CXCL12 heterodimer comes from the critical role of the CXCL12 chemokine and its receptor, CXCR4, in invasion, migration, and proliferation steps of tumor progression in more than 75% of all cancers, including breast, ovarian, lung, colon, prostate, kidney, melanoma, brain, esophageal, pancreatic, and various forms of leukemia50,51.