Hypoxia and modulation of cellular radiation response

Tumors possess many features that differentiate them from normal tissues which can potentially be targeted for therapy. One such difference is the presence of an inefficient vascular network, which is often unable to meet the tumor's needs. The interaction of this faulty vascular system with the cells within the tumor leads to the development of a unique tumor microenvironment not found in normal tissues. This particular environment has a number of distinct features such as low oxygen concentrations, high interstitial fluid pressures and low pH. Previous studies have found that the presence of these microenvironmental conditions potentiates the development of certain adaptive responses by the tumor. These adaptive responses can have a number of adverse consequences, including increased resistance to chemo and radiotherapy. Nevertheless, since these microenvironmental characteristics are found in most solid tumor types, they have a profound effect on the tumor's behavior and represent attractive therapeutic targets. © Springer Science+Business Media, LLC 2011.