Aim According to various target sites of HLA-E mRNA,to design and synthesize 3 pieces of HLA-E siRNA chain,to compare quantitatively their efficiency of silencing gene in BEL-7402 with HLA-E(+)in order to select the dominant siRNA.Methods The hepatocarcinomal BEL-7402 cells,induced by 5×10~5 IU·L~(-1) IFN-γ,expressed HLA-E(+) and was pured by flow cytometry selecting as target cells for research.3 pieces of specific siRNA(A,B,C group)were designed and chemically synthesized,then the concentration of which(0.1 mmol·L~(-1))was respectively transfected through Lipofectamin 2000 into target cells.After 48 h,the gene silent effect on HLA-E gene in A,B and C groups was quantitatively observed by cytoimmunofluorence,flow cytometery,Western blot and real-time PCR,as well as on NK cytotoxicity to target cells tested by NK killing rate.Results Compared with those of control or non-specific siRNA group,HLA-E antigen,protein product,HLA-E mRNA and HLA-E molecule on cell surface were statistically down-regulated in A,B,and C group(P<0.01),whose were silenced more (above 90%) in B or C group than in A group (P<0.01).The NK killing rate in A,B and C groups was dominantly improved(P<0.01),which in B or C group was higher than in A group (P<0.01).Conclusion The targeted siRNA can specifically and high-efficiently silence HLA-E expression in hepatocarcinomal cells,and may keep them from immunoescape through non-classic HLAⅠ pathway to imply new strategy for hepatocarcinomal gene-immunotherapy.