KRAS and cancer: Intensive research, attempting to correlate the benefits from EGFR-targeted therapy with EGFR presence, EGFR mutation (NSCLC), EGFR gene amplification (NSCLC), EGFR pathway dependence or downstream mutations (conveying resistance to EGFR therapy, such as K-ras mutation in colorectal carcinoma) is currently underway, and most likely will provide different answers for different cancer histologies.