ALK Fusion Protein Expression in Lung Adenocarcinoma and its Correlation with EGFR Protein Expression

Abstract

Aim: To determine ALK fusion protein and EGFR protein expression by Immunohistochemistry in lung adenocarcinoma. Materials and Method:In this retrospective study, ALK and EGFR expression was evaluated by immunohistochemistry in 101 Formalin Fixed Paraffin Embedded (FFPE) tissues of lung adenocarcinoma.Results: In this study 11% patients showed ALK fusion protein expression. In relation to clinical parameters, a higher positive expression was observed in patients with age <59, in male gender and tobacco users. Further, with pathological parameters a higher expression of ALK was observed in advanced stage and positive lymph node status. EGFR expression was noted in 72% patients. In relation to clinical parameters, higher EGFR expression was seen in patients with age >59 years, in male gender with tobacco habit. Further, with pathological parameters, a trend of higher EGFR expression was observed in patients with positive lymph node status (p=0.06). In this study 8% of patients had ALK and EGFR dual expression, which is uncommon. Conclusion:Small group of NSCLC patients harbour ALK rearrangements which are candidate for targeted therapy (Crizotinib). Moreover, co-expression of ALK with EGFR defines a specific subgroup of patients that needs distinct therapeutic strategies.