Mini Review: Immunohistochemistry Using EGFR-Mutant Specific Antibodies in Non-Small Cell Lung Carcinoma: Accuracy and Reliability

Abstract

Epidermal growth factor receptor (EGFR) is a predictive biomarker in many solid cancers including non-small cell lung carcinoma (NSCLC). Patients’ responsiveness to therapy is based on the prior determination of EGFR status. Many techniques were used to detect the potential predictive biomarker and considered as gold standards based on molecular genetic techniques as direct sequencing and polymerase chain reaction (PCR). Immunohistochemistry (IHC) using EGFR mutation-specific antibodies were generated as an alternative simple tool to identify EGFR status and its response to tyrosine kinase inhibitors (TKIs). EGFR gene copy number and wild-type EGFR are other parameters which determine the response to TKIs. The aim of this mini-review is to analyze the studies which investigated the IHC EGFR mutation-specific antibodies, in lung adenocarcinoma (ADC), to determine its accuracy and reliability as a pre-selection tool for candidate patients for TKIs therapy as well as the interplay with other EGFR biomarkers which are EGFR gene copy number and the wild-type EGFR in lung NSCLC. The later determine the response to TKIs and their detection methodology is standardized making them good candidates for comparison with the EGFR-mutation.