In the present study, we reconfirmed that a subset of NSCLC patients who were treated with EGFR TKIs did not experience marked tumor shrinkage despite the presence of EGFR mutations and clearly demonstrated that PS and OS strikingly differed in non-responders and responders (1.8 vs. 10.3 months, P<0.0001 and 9.4 vs. 17.3 months, P = 0.0008, respectively). The gene discussed is EGFR; the disease is neoplasm.