Immunohistochemistry comparison of Napsin A and CK7 expression in primary lung adenocarcinoma

Abstract

Background: Lung cancer is the most common cancer worldwide and the leading cause of cancerrelated death. Lung carcinomas are broadly divided into small cell carcinoma and non-small cell lung carcinoma (NSCLC). Non-small cell lung cancer accounts for 80% of lung cancers and lung adenocarcinoma is one of the main types of NSCLC. Here we studied the significance of the commonly used lung adenocarcinoma diagnostic markers, including TTF-1, Napsin A and CK7, in the diagnosis of lung adenocarcinoma using immunohistochemical (IHC) analysis. Aim: To evaluate and compare the significance of IHC markers, CK 7 and Napsin A in diagnosis of lung adenocarcinoma as far as specificity and reliability are concerned. Material and Methods: This study was conducted over a period of 5 years, from 2018 to 2022 which included all cases diagnosed as lung carcinoma on tissue biopsies and later subjected for IHC using relevant markers like CK7, TTF-1, Napsin-A, CK5/6, p63, Synaptophysin and Chromogranin A. 47 cases of lung adenocarcinoma were selected from the retrospective database of lung cancer. Results: Among the 47 cases of lung adenocarcinoma. IHC was done on 41 cases (87.23%). Immunocytochemistry (ICC) was done on 6 cases (12.8%). Lung adenocarcinoma IHC markers study shows CK 7 positive and Napsin-A negative in 21 cases (51.2%). CK 7 negative and Napsin-A positive only in 1 case (2.4%). Both are positive in 16 cases (39.0%) and both were negative in 3 cases (7.3%). ICC was studied in total 6 cases which show CK 7 positivity in 4 cases (66.7%). Only 2 case of ICC show Napsin-A positivity (33.3%). Conclusion: As far as IHC is concerned CK 7 is more reliable and specific than Napsin-A in diagnosis of primary lung adenocarcinoma.