CXCL12 and breast neoplasm: The other anti-HIV SDF-1 competitor, Nef-M1, an apoptotic peptide that encompasses the residues 50 to 60 of the HIV-1 Nef protein (sequence: Thr–Asn–Ala–Ala–Cys–Ala–Trp–Leu–Glu–Ala–Gln), not only inhibits the growth of primary breast tumors and related metastasis [128,129], but also prevents breast tumor angiogenesis and epithelial-to-mesenchymal transition [130].