EGFR Expression Frequency in Non-Small Cell Lung Cancer: An Immunohistochemical Study

Abstract

Background: Epidermal Growth Factor Receptor (EGFR) overexpression is commonly observed in non-small cell lung cancer (NSCLC) and is associated with tumor progression and poor prognosis. Objectives: To determine the frequency of EGFR expression in non-small cell lung cancer using immunohistochemical analysis. Methodology: This cross-sectional study study was conducted at Rehman Medical College, Peshawar from Jan 2021 to June 2021, where formalin-fixed, paraffin-embedded (FFPE) tissue samples from patients diagnosed with NSCLC between January 2020 and December 2021 were collected. The study included 125 patients with a confirmed histopathological diagnosis of NSCLC who had not received prior EGFR-targeted therapy. Immunohistochemical staining for EGFR was performed on 4-μm-thick sections of FFPE tissue samples. The evaluation of EGFR expression was performed by two independent pathologists who were blinded to the clinical data. Data were analyzed using SPSS version 27. Results: The study included 125 NSCLC patients with a mean age of 60.3 years. The gender distribution was nearly even, with 52% male and 48% female patients. Adenocarcinoma was the most common histological subtype (60%), followed by squamous cell carcinoma (32%) and large cell carcinoma (8%). This data provides a clear demographic and clinical profile of the study population. The study found that 44% of the NSCLC patients (55 out of 125) had positive EGFR expression, with a combined immunohistochemistry score of 2 or higher. Conversely, 56% of the patients (70 out of 125) showed negative EGFR expression, with a score below 2. Conclusion: The study reveals that nearly half of the NSCLC patients exhibit positive EGFR expression, indicating a potential target for targeted therapies. This finding underscores the importance of EGFR status in the clinical management of NSCLC and highlights the need for further research to optimize treatment strategies.