NK cells can be rapidly activated to attack certain abnormal cells spontaneously through producing large inflammatory cytokines (eg: TNF-α, IFN-γ etc.)and chemotactic factors (eg: CCL3, CCL4, CXCL10 etc.)in vivo24, especially tumor or virus infected cells, so lack of NK cells increased susceptibility to viral infections and possibility to tumorigenesis35. This evidence concerns the gene CCL3 and neoplasm.