STUDY OF EXPRESSION OF EGFR AND ALK BY IMMUNOHISTOCHEMISTRY IN NON-SMALL CELL LUNG CARCINOMA

Dr. Nabanita Barma; Dr. Moumita Maiti; Dr.(Prof) Ranu Sarkar; Dr. Moumita Pal; Dr. Nipamanjari Barman

Volume : VIII, Issue : II, February - 2019

STUDY OF EXPRESSION OF EGFR AND ALK BY IMMUNOHISTOCHEMISTRY IN NON-SMALL CELL LUNG CARCINOMA

Dr. Nabanita Barma, Dr. Moumita Maiti, Dr. Prof Ranu Sarkar, Dr. Moumita Pal, Dr. Nipamanjari Barman

Abstract :

Background: Epidermal growth factor receptor (EGFR), a cell surface protein, is overexpressed in 27–44% of non–small cell lung carcinoma (NSCLC) cases of Indian Ethnicity. First line treatment with EGFR tyrosine kinase inhibitors, in combination with conventional radiotherapy or chemotherapy, has shown uncontested benefits by increasing overall survival.

A fusion gene between echinoderm microtubule–associated protein–like 4 (EML4) and anaplastic lymphoma kinase (ALK), named EML4–ALK, has been identified in a subset of non–small–cell lung carcinoma cases, and, when inhibited by ALK inhibitors, has shown response rates of more than 60%.

Aim: The objective of this study was to find out the prevalence of EGFR and ALK expression in histologically diagnosed cases of NSCLC, to evaluate their clinical characteristics.

Material and methods: A total of 67 histopatholologically diagnosed cases of non–small cell lung carcinoma were included. Formalin fixed, paraffin–embedded blocks were evaluated for EGFR and ALK expression by immunohistochemistry and their expressions were compared with clinico–pathological variables such as age of presentation, sex, smoking habit, histological type, stage etc. Spearman correlation test has been used to find the significance of study parameters on categorical scale between two or more groups using statistical software MedCalc V 11.3.0.0.

Results: The incidence of EGFR positivity (42%) in this study population is close to the reported incidence in Asian patients. Here we found a positive correlation of EGFR expression with female gender, and non– smoker patients. The positivity for ALK IHC in our study is 4%, and demonstrates a positive correlation with younger age at presentation.

Conclusion: As the high likelihood of response to EGFR and ALK tyrosine kinase inhibitors can improve the overall survival of the patients and avoid the unnecessary side effects of conventional chemotherapy, it emphasizes the importance of detection of EGFR and ALK expression in non–small cell lung carcinoma cases.