CXCR4 silencing inhibits cell growth in human carcinoma cell lines45 and increased expression of CXCR4 in G2/M phases has been reported in breast cancer cell lines where proteomic analysis revealed crosstalk between CXCR4 and G2‐M transition proteins, such as PLK1 and Cyclin B1.46 This evidence concerns the gene PLK1 and breast cancer.