PECAM1 and neoplasm: To test potency of SIP‐11 in vivo, tumour‐bearing athymic mice received peptide treatment via tail vein, which led to decrease in 18F‐flurodeoxyglucose (FDG) uptake, growth, weight, glycolysis, SPI1 target gene expression, Ly6G+ neutrophils, Ki‐67 expression and CD31‐staining microvessel density of subcutaneous xenograft models generated by injection of HCT116 cells into nude mice (Figures 7I, J and S10A–D).