Immunohistochemical analysis and comparison of napsin A, TTF1, SPA and CK7 expression in primary lung adenocarcinoma.

We investigated the expression of napsin A, TTF1, SPA and CK7 in primary lung adenocarcinoma (ADC) and compared antibody specificity and sensitivity. We used immunohistochemistry (IHC) using antibodies directed against napsin A, TTF1, SPA, and CK7 on cancer tissue from 454 patients diagnosed with lung cancer. In primary lung ADC, napsin A exhibited a sensitivity of 87.25% and specificity of 95.02%, TTF1 exhibited a sensitivity of 80.72% and specificity of 90.48%, SPA exhibited a sensitivity of 60.46% and specificity of 94.87% and CK7 exhibited a sensitivity of 100% and specificity of 80.31%. The order of sensitivity of the four indicators was CK7 > napsin A > TTF1 > SPA, and the order of specificity was napsin A > SPA > TTF1 > CK7. We can select effective indicators for diagnostic and differential diagnostic purposes based on differences in sensitivity and specificity.