Loss of PTEN function has been reported in CRC (Thomas and Grandis, 2004) and may represent one of the resistance mechanisms interfering with the response to EGFR antagonists by dissociating EGFR inhibition from the downstream phosphatdylinositol 3-kinase/Akt pathway (Baselga, 2001). This evidence concerns the gene EGFR and colorectal carcinoma.