Although IL13Rα2 expression in the SK-MEL-28 cells slightly upregulated the expression of vascular endothelial growth factor (VEGF), a well-known tumour angiogenic factor, the upregulation can be considered minimal (1.5-fold), compared to that of amphiregulin (3.2-fold) (Figs 6 and S6). This evidence concerns the gene AREG and neoplasm.