Gene expression alterations in human colon cancer xenograft treated with anti-VEGF antibody

Recent randomized clinical trial revealed the additional effect of bevacizumab, a humanized monoclonal antibody against vascular endothelial growth factor (VEGF)-A, to conventional chemotherapy on survival of patients with metastatic colorectal cancer. However, a number of preclinical reports indicate resistant mechanisms to anti-angiogenic therapy in several tumor models. We investigated the phenotypic alterations of colorectal cancer xenograft during antiangiogenic therapy. TK-4, a solid tumor strain derived from human colon cancer, was orthotopically implanted into cecal walls of nude mice and treated with anti-VEGF antibody or control IgG for 35 days. Gene expression was analyzed using microarrays (Human Gene 1.0ST Array, Affymetrix).