In addition, a detailed analysis of the tumour tissues derived from the A375-IL13RA2 KO cells showed a dramatic decrease in the number of PECAM-1-positive vessels (Fig. 5E,F) indicating that new vessel formation was strongly affected by the absence of IL13Rα2 expression and revealing it to be indispensable for A375 tumour formation and angiogenic events. Here, PECAM1 is linked to neoplasm.