This unit (1) provides background into understanding how agents that target specific molecules or receptors (molecular-targeted agents), in particular, agents affecting the tumor vasculature (perivasculature network in tumors), interact with and modify radiation therapy; (2) details factors affecting interpretation of results in murine tumor model experiments utilizing radiation therapy and drug combinations; and (3) provides specific protocols for the application of radiation therapy, both alone and in combination with chemotherapy and/or molecular-targeted agents.