LDLR and neoplasm: Preformed, lipophilic sensitisers, such as the porphyrins and phthalocyanines, when administered intravenously, are believed to be transported in the bloodstream bound to lipoproteins, such as low density lipoproteins (LDLs).14,20 Tumour cell membranes are known to possess disproportionately high numbers of LDL receptors,21 leading to active accumulation of photosensitiser molecules at close proximity to tumour cells.