ABSTRACT
The majority lung tumors are classified as Non-Small Cell Lung Carcinomas (NSCLCs) and Small Cell Carcinomas (SCCs). NSCLC needs to be further subclassifed into adenocarcinoma and squamous cell carcinoma for better treatment options. Napsin A and P40 are emerging as potential markers for the subclassification of adenocarcinoma and squamous cell carcinoma. So the present study evaluated expression of Napsin A and P40 in lung adenocarcinoma and SCC patients so as to evaluate its diagnostic utility, and correlate and check its sensitivity and specificity along with other diagnostic lung cancer markers. Expression of Napsin A and P40 was evaluated in 25 adenocarcinoma and 25 squamous cell carcinoma patients by Immunohisotochemistry. Napsin A expression was observed in 42% and P40 in 64% of the patients. The expression of Napsin A was significantly higher in adenocarcinoma patients with a positive correlation with adenocarcinoma markers Thyroid Transcription Factor 1(TTF-1) and Cytokeratin 7(CK7); and inverse correlation with squamous cell marker Cytokeratin 5/6(CK5/6) with a specificity of 76% which was highest and sensitivity of 60%, which was lower than that of CK7, Carcino Embryogenic antigen(CEA) and TTF-1 in adenocarcinoma patients. The expression of P40 was significantly higher in squamous cell carcinoma and patients with metastasis, along with higher incidence in patients with increased tumor size and advanced disease stage. P40 showed positive correlation with squamous cell marker p63 and CK 5/6 with a specificity of 52% and sensitivity of 80% in squamous cell carcinoma patients but was lower than CK5/6 and p63. Napsin A was found be most specific adenocarcinoma marker, but its sensitivity was low. Further, P40 failed to reach highest level of sensitivity and specificity in our set of patients which may be due to the less number of patients analyzed in the study and urges a need to be evaluated in a large cohort