The growth of the lung carcinoma xenografts was inhibited by the 2′-O-methyl-modified siRNACD31 and RNAi-mate complexes, and the expression of the PECAM-1 protein was downregulated, with a simultaneous decrease in vascular endothelial growth factor (VEGF) protein in the lung carcinoma xenografts. The gene discussed is PECAM1; the disease is lung carcinoma.