Clinicopathological Profile of Anaplastic Lymphoma Kinase-positive Nonsmall Cell Lung Cancer: An Indian Perspective

Abstract

Abstract Background: A novel fusion gene of echinoderm microtubule-associated protein-like 4 (EML4) and anaplastic lymphoma kinase (ALK) has been identified in a subset of non-small-cell lung cancers (NSCLCs). Patients with the ALK-EML4 fusion gene demonstrate unique clinicopathological and physiological characteristics. Here we present an analysis of clinicopathological profile of patients of metastatic adenocarcinoma harboring the ALK-EML4 fusion gene. Methods: A retrospective analysis of advanced ALK positive NSCLC, who presented at this tertiary care hospital of armed forces from September 2014 to December 2016 was conducted. The primary goal was to evaluate demographic and clinicopathological profile of ALK positive advanced NSCLC. Detection of ALK fusion was done by IHC on formalin fixed paraffin embedded cell blocks. Results: Out of 270 patients of NSCLC, 15 (7.4%) tested positive for ALK-EML4 fusion. Rate of positivity was higher in females (13.7%) than in males (5%). The correlation of the ALK-EML4 fusion gene and clinicopathological characteristics of NSCLC patients demonstrated a significant difference in smoking status, histological types, stage, and metastatic pattern. Conclusion: Our analysis indicated that ALK-EML4 positive NSCLC comprised a unique subgroup of adenocarcinomas with distinct clinicopathological and radiological characteristics. Incidence of ALK positivity was found to be higher in females and never smokers. These patients have distinct pathological and radiological characteristics.