VEGFA and colorectal cancer: An ELISA that strictly distinguishes between VEGF-A121 and VEGF-A165—the major isoforms of VEGF-A—and a commercially available ELISA for VEGF-A are used to determine the concentration of VEGF-A121, VEGF-A165, and VEGF-A in the blood of 12 patients with advanced colorectal cancer receiving bevacizumab therapy.