One example very relevant to CRC, is the finding that mutation of the KRAS (V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog) gene is a strong negative predictor for responsiveness of patients to the EGFR-targeted agents, cetuximab and panitumumab (Banck and Grothey, 2009; Prenen et al., 2010; Siddiqui and Piperdi, 2010). This evidence concerns the gene EGFR and colorectal carcinoma.