TPP1 and neoplasm: Regarding the mechanism, ITPP is an allosteric effector that reduces the oxygen‐binding affinity of haemoglobin and thus facilitates the oxygen release by red blood cells.20, 21 In addition, long‐term ITPP administration has been shown to lead to vascular normalization through the down‐regulation of HIFs/VEGF with a consequent increase in the oxygen supply to tumours.15, 17, 18 To determine possible contributing factors to the increase in oxygenation, we assessed the effect of ITPP on tumour perfusion and on cancer cell OCR.