Tumor endothelial marker-1 also referred to as TEM-1 is expressed in the supportive tissue, as well as, on the cells within the tumor. TEM-1, which is a cell surface glycoprotein, and is expressed in the stromal compartment (cells) of nearly all human tumors. In preclinical studies, it has been shown that TEM-1 plays a key role in tumor growth and the vascularization of tumors. There is evidence suggesting an association between the level of TEM-1, 7, 7R, 8 in relation to lymph node involvement and disease progression. MORAb-004 is a humanized immunoglobulin G (IgG1/κ) antibody directed against endosialin/TEM-1. Nonclinical pharmacological studies showed that MORAb-004 has the ability to block specific TEM-1 receptor-ligand interactions. Immunohistochemistry studies of human tumor biopsy samples demonstrate TEM-1 expression and MORAb-004 binding to tumor stromal cells, in particular mural cell compartment of neovessels and cancer-associated fibroblasts. All of which suggests a potential effective treatment. Researchers hypothesize that an antibody therapy that binds to TEM-1 may be efficacious in the treatment of metastatic, colorectal cancer. This clinical study is a proof of concept study to see if an anti-TEM-1 agent is safe and effective in the treatment of metastatic, colorectal cancer.