Exploiting the hypoxic cancer cell: mechanisms and therapeutic strategies

Human solid tumours are considerably less well oxygenated than normal tissu es, This leads to resistance to radiotherapy and anticancer chemotherapy, a s well as predisposing to increased tumour metastases, However, tumour hypo xia can be exploited in cancer treatment. One such strategy is to use drugs that are toxic only under hypoxic conditions, and the first drug of this c lass to enter clinical testing, tirapazamine, is showing considerable promi se, The second way to exploit hypoxia is to take advantage of the selective induction of the transcription factor hypoxia-inducible factor 1 (HIF-1) u nder hypoxic conditions; gene therapy strategies based on this are in devel opment.