The concept of combining cancer vaccination with angiogenesis inhibition is appealing, due to favorable safety profile of both approaches, as well as possible biological synergies [54] . DNA vaccination in mice against the VEGF receptor, FLK-1, abrogated the tumor vasculature and protected DNA vaccinated animals from tumor challenge in prophylactic approach [126] . Expression of the plateletderived growth factor receptor (PDGFR) in stromal cells directly correlates with advanced stage disease in human colorectal cancer. DNA vaccine against PDGFRβ suppressed 8 Journal of Biomedicine and Biotechnology growth and dissemination of human colorectal cancer cells injected into mice [127] .