Therefore we hypothesized that HGF induces Rac recruitment at ruffling sites, which may prolong the membrane expression of CXCR4/Rac-1, and reduce the CXCR4 endocytosis caused by chemoattractants and/or CXCR4 antibodies, thereby stimulating the chemotaxis and migration of tumor cells. This evidence concerns the gene RAC1 and neoplasm.