Clinicopathological and immunohistochemical profile of non-small cell lung carcinoma in a tertiary care medical centre in South India

BACKGROUND: Lung cancer is a highly aggressive malignancy causing high morbidity and mortality. An increasing incidence of lung cancer has been observed in India. Currently, the classification of lung carcinoma has gone beyond small cell lung carcinoma and non-small cell lung carcinoma (NSCLC). Precise subtyping of poorly differentiated NSCLC into adenocarcinoma and squamous cell carcinoma has a direct impact on patient management and prognosis. With this background, many molecules are under study for developing targeted therapies. Epidermal growth factor receptor (EGFR) is one such biomarker considered to be useful in targeted therapy for adenocarcinoma. OBJECTIVE: The aim of this study was to subtype poorly differentiated NSCLC based on the expression of thyroid transcription factor-1 (TTF-1) and p-63 and to evaluate EGFR expression in adenocarcinomas. MATERIALS AND METHODS: A retrospective analysis of 84 cases of poorly differentiated carcinomas of the lung was performed. Paraffin sections were immunostained with TTF-1 and p-63 and the tumors were subtyped. EGFR expression was assessed in adenocarcinomas by immunohistochemistry. RESULTS: Fifty-five percent of the NSCLC were adenocarcinoma, with a peak incidence between 61 and 70 years of age and a male predominance. EGFR was expressed in 89% of the adenocarcinomas. CONCLUSIONS: Poorly differentiated non-small cell carcinoma can be subtyped by immunohistochemical markers and hence has a direct impact on the current therapeutic strategies.