The present invention relates to biomarkers for colon cancers, specifically adenomas and adenocarcinomas in the GI tract. The inventors have discovered that the expression and/or overexpression of biomarkers such as CLDN1, GPR56, GRM8, LY6G6D, TLR4 and SLCO1B3 are indicative of adenomas and adenocarcinomas. A method of detecting colon cancer using targeted molecular imaging agents is also presented.