At the time of completion of radiotherapy, the mean values of VEGF and CD31 were significantly higher in cases with active colitis in histology examination compared to those showing no activity (0.55 ± 0.12 versus 0.24 ± 0.23, P = 0.012 and 8.95 ± 1.9 versus 6.08 ± 1.43, P = 0.02, resp). This evidence concerns the gene PECAM1 and colitis.