AREG and non-small cell lung carcinoma: In contrast, increased levels of serum AREG have been correlated with a lack of benefit from gefitinib treatment in patients with advanced NSCLC [32, 33], and in an independent study AREG overexpression was reported to promote resistance to gefitinib-induced apoptosis rather than sensitivity in KRAS mutant NSCLC cell lines [34, 35].