The ratio of cells that are positive for endothelial cell marker CD31 to cells that are positive for pericyte marker neural/glial antigen (NG2) is a key indicator of vascular normalization.25 We found that there was a significant decrease in the CD31+/NG2+ cell ratio in tumour vessels after neoadjuvant treatment compared with baseline (Fig. 3a, b). Here, PECAM1 is linked to neoplasm.