PECAM1 and neoplasm: We first performed double staining for CD31 and Nogo-B in serial sections of HCC tissues by immunohistochemistry (Supplementary Figure S1A,B) and then performed laser capture microdissection to harvest CD31-positive vascular endothelial cells from the tumor and peri-tumor tissues from 10 patients with HCC (Figure 1A) to examine Nogo-B expression in vascular endothelial cells from HCC.