PECAM1 and neoplasm: Endothelial p53 reduction mitigated these radiation-driven effects: in EC-p53KD (Tie2-Cre;Trp53flox/+) and EC-p53KO (Tie2-Cre;Trp53flox/flox) mice bearing KP tumors and exposed to irradiation, the increases seen in wild type—α-SMA+/CD31+ partial EndMT, collagen deposition, tumor size, and the number of metastatic nodules—were markedly reduced.