Aims: Overexpression and mutation of epidermal growth factor regulator (EGFR) are frequently found in the carcinogenesis of non-small cell lung cancer (NSCLC). Because targeting of this receptor has proven therapeutic efficacy, studying EGFR has become a matter of particular scientific interest. The present study analysed the EGFR receptor, rate of EGFRvIII mutations, and rate of activated phosphorylated EGFR (pEGFR) by immunohistochemistry on cryostat sections.
Methods: Surgically obtained tumour specimens of a series of 78 NSCLC patients and 66 adjacent tumour free specimens were examined immunohistochemically using monoclonal antibodies to stain EGFR, pEGFR, and EGFRvIII.
Results: EGFRvIII and pEGFR expression was found in 42% and 26% of the tumours respectively and both were increased significantly compared with tumour free samples. EGFR, pEGFR, and EGFRvIII expression did not correlate with any of the previously tested markers (c-erbB-2, c-erbB-3, p53, ki-67, and microvessel density). Similar distributions of immunohistochemical profiles were seen, regardless of histological subtype, age, or sex. In stage I patients, EGFR phosphorylation at tyrosine residue 845 proved to be an independent prognostic factor.
Conclusion: Because pEGFR correlated with poor prognosis, it can be speculated that it plays a crucial biological role in the pathogenesis of NSCLC.