PECAM1 and neoplasm: EndMT (SMA+CD31+) cells in WT tumours were less TUNEL– or γH2AX– at 3 dpi, but highly Ki67+ (indicative of cell proliferation) during tumour regrowth (23 dpi), in contrast to SMA− ECs in EC-p53KO mice (Fig. 1i and Supplementary Fig. 4d, e).