A previous study investigated the role of p53 in growth-inhibitory and apoptotic effects of gefitinib in the human NSCLC cell lines NCI-H1299 and A549, which have no EGFR mutations and found that p53 enhanced gefitinib-induced growth inhibition and apoptosis by regulation of Fas (factor associated suicide) in NSCLC (52). Here, FAS is linked to non-small cell lung carcinoma.