The albumin-binding dye Evans Blue, widely used as a physiological marker of vascular permeability [5], and N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer–GFLG–Dox (FCE28068) (Fig. 1), a conjugate that has undergone Phase I/II clinical trials [11, 12], were selected as probes of the EPR effect in tumour models. Here, ALB is linked to neoplasm.