HSPE1 and neoplasm: We found that the tumour homing of these NPs at 5 and 48 h post injection was strongly affected by their low plasma availability, as demonstrated by the total lack of a detectable Epf signal in supine mice (Fig. 5c and Supplementary Fig. 13) and FI in tumour homogenates (Fig. 5e), and by a very low Epf in dissected tumours (Fig. 5d and Supplementary Fig. 13).