Conclusive research has shown that regions of acute/chronic hypoxia, which exist 
within the majority of solid tumours, have a profound influence on the 
therapeutic outcome of cancer chemotherapy and radiotherapy and are a strong 
prognostic factor of disease progression and survival. A strong argument 
therefore exists for assessing the hypoxic fraction of tumours, prior to patient 
treatment, and to tailor this treatment accordingly. Tumour hypoxia also 
provides a powerful physiological stimulus that can be exploited as a 
tumour-specific condition, allowing for the rationale design of 
hypoxia-activated anticancer drugs or novel hypoxia-regulated gene therapy 
strategies.