Comparison of immunohistochemistry and mRNA in situ hybridization in detecting thyroid transcription factor-1 expression in non-small cell lung carcinomas tissue.

Thyroid transcription factor-1 (TTF-1) reportedly possesses oncogenic and suppressive roles within the same tumor type and may play a dual function in the progression of lung cancer. Immunohistochemistry (IHC) and mRNA in situ hybridization (ISH) are commonly used methods for detecting protein or mRNA expression. The present study compared the concordance rate of the two methods in the evaluation of thyroid transcription factor-1 (TTF-1) expression in non-small cell lung carcinoma (NSCLC) using tissue microarray-based IHC and mRNA ISH. TTF-1 protein and mRNA expression levels were examined in 196 cases of NSCLC. The IHC and mRNA ISH agreement was 91.3% (179/196), and near-perfect agreement was observed between the two methods (κ-coefficient, 0.848). There was no significant difference between IHC and mRNA ISH, as analyzed by the McNemar-Bowker test (P=0.219). The present findings proved that IHC is comparable to mRNA ISH for evaluating TTF-1 expression in NSCLC. These two methods can be used to detect TTF-1 expression in future studies.