Various whole cell extracts (30 μg) were separated by 7.5% SDS-PAGE, and the membrane was blotted with CD31 antibody [HL4073] (GTX642512) diluted at 1:1000. The HRP-conjugated anti-rabbit IgG antibody (GTX213110-01) was used to detect the primary antibody. Corresponding RNA expression data are based on Human Protein Atlas program.