Diagnostic Value of Immunohistochemistry Panel of P۶۳, CK۵/۶, TTF۱, NapsinA in the Diagnosis of Adenocarcinoma and Squamous Cell Carcinoma of Lung

Background: Lung cancer is one of the most frequently diagnosed malignant neoplasms in the world. The pulmonary carcinomas are divided into two major categories, namely small cell lung carcinoma (SCLC) and non-small cell lung carcinoma (NSCLC).Traditionally, the treatment for NSCLC was based on tumor stage, irrespective of histologic subtypes; over the recent years, however, with the development of targeted therapies with different adverse or therapeutic effects on each subtype, it is crucial to correctly subcategorize NSCLC. Utilizing Immunohistochemical (IHC) markers may be conducive to obtain this objective, yet no single marker is sensitive or specific enough to differentiate SCC and adenocarcinoma. Therefore, in the present research, we want to use a panel consisting of P۶۳, CK ۵/۶, TTF-۱, and Napsin A. Methods: ۸۳ cases of NSCLC (۳۶ adenocarcinoma, ۳۷ squamous cell carcinoma and ۱۰ poorly differentiated carcinoma) were selected. IHC examination for P۶۳, TTF-۱, Napsin A, and CK ۵/۶ were performed on tissue sections obtained from formalin-fixed, paraffin embedded blocks. Results: TTF۱ had ۹۴% sensitivity and ۶۹% specificity with PPV ۷۳% and NPV ۹۲%, and NaspsinA had ۹۱% sensitivity and ۹۷% specificity with PPV ۹۷% and NPV ۹۲% as regards the diagnosis of adenocarcinoma. P۶۳ had ۱۰۰% sensitivity and ۸۴% specificity with PPV ۸۷% and NPV ۱۰۰%, and CK۵/۶ had ۱۰۰% sensitivity and ۶۹% specificity with PPV ۷۸% and NPV ۱۰۰% in the diagnosis of squamous cell carcinoma. Conclusion: Using an IHC panel of TTF-۱, Napsin A, P۶۳, and CK۵/۶ it is possible to reliably diagnose poorly differentiated NSCLC with no evident glandular or squamous differentiation.

Keywords:

Lung , Adenocarcinoma , Squamous cell carcinoma , Napsin A , TTF۱ , P۶۳ , CK۵/۶