As Src kinase family was described as a player in CXCL12/CXCR4 and PI3K or MAPK pathway in severe solid tumor, we hypothesized whether HCK could be a downstream target of CXCL12/CXCR4 pathway and contribute to the pathophysiology of leukemia cells. The gene discussed is CXCL12; the disease is leukemia.