Besides, although the detection of KRAS mutation status before MoAbs therapy is widely accepted, there is little agreement on its predicted and prognostic role, for published studies provided different results in the relationship between KRAS mutation and clinical outcomes in CRC, and the main effectors in downstream signaling pathway of KRAS, such as BRAF, PIK3CA and NRAS were already studied in many clinical trials, which showed the capability to present as potential predictive or prognostic biomarkers [14], [19]. The gene discussed is PIK3CA; the disease is colorectal carcinoma.