CXCL12 and cancer: Among the genes encoding chemokines, C-C chemokine receptor type 2 (CCR2) rs1799864 [85–87] and CCR5 rs333 [85] were associated with an increased risk for BC in the Turkish population, rs1801157 in C-X-C motif chemokine 12 (CXCL12) also has a positive association with BC in Indian [88] and Turkish [85] populations; and rs1126579 in CXC chemokine receptors 2 (CXCR2) increases cancer’s susceptibility in the Indian population [88] while it shows a protective effect towards BC in the American population [89].