CXCR4 is widely overexpressed in various cancer cells, including MDA-MB-231 breast cancer cells [42], 8505C thyroid cancer cells [43], Hs766t pancreatic cancer cells [44], Jurkat T cells, and U937 and THP-1 monocytic leukemia cells [45, 46]. This evidence concerns the gene CXCR4 and breast cancer.