PECAM1 and neoplasm: Immunostaining of vascular markers showed an increase in tumor cells co-expressing GFP with VE-CADHERIN or CD31 (endothelial) and DESMIN or αSMA (pericyte) predominantly in the tumor mass, and only 1-2 cells per section in the vessels, in radiated tumors compared to non-radiated tumors (Fig. 2h, Supplementary Fig. 2m).