It was rationalised by cancer tissues having disorganised, leaky blood vessels with deficient basement membranes (BMs),33 as well as lacking a functional lymphatic system for efficient clearance of the NPs.73 Also thought to contribute to the elevated vascular permeability were factors actively produced by tumour cells, including bradykinin,74,75 nitric oxide (NO) and peroxynitrite (ONOO–)76 and vascular endothelial growth factor (VEGF),77 as well as other inflammatory mediators. This evidence concerns the gene VEGFA and cancer.