KRAS and non-small cell lung carcinoma: Based on the evidence generated from the studies described thus far, the EGFR mutation status appear to be the most consistently found predictive biomarker for EGFR TKI or mAb efficacy in advanced NSCLC while other potential markers, such as KRAS mutation and EGFR gene copy number, need to be further evaluated in larger cohort of patients in the future.