2′-O-methyl-modified siRNACD31 successfully downregulated the PECAM-1 mRNA and protein expression of the EOMA cells using RNAi-mate as a carrier in vitro (Fig. 3), and the expression of PECAM-1 was detected by immunohistochemical examinations in the vasculature of the lung adenocarcinoma xenografts (Fig. 4A) and in the vascular tissues of the lung, liver, heart, brain and kidney in vivo (Fig. 4B–F). This evidence concerns the gene PECAM1 and lung adenocarcinoma.