Recent clinical trials have revealed that accurate histologic typing of non–small cell lung cancer is essential. Until now, squamous cell carcinoma (SQC) and adenocarcinoma (ADC) markers have not been thoroughly analyzed for pulmonary neuroendocrine carcinomas (NECs). We analyzed the expression of 8 markers [p63, cytokeratin (CK) 5/6, SOX2, CK7, desmocollin 3, thyroid transcription factor-1 (8G7G3/1 and SPT24), and napsin A] in 224 NECs. SOX2 (76.2%) had the greatest expression for NECs. CK5/6 (1.4%), desmocollin 3 (0.5%), and napsin A (0%) were expressed less or not at all in NECs. Although our investigated markers have been reported useful for differentiating between SQC and ADC, some of them were also present in a portion of pulmonary NECs. In our study, CK5/6 and desmocollin 3 were highly specific markers for SQC, and napsin A was highly specific for ADC. These markers are recommended for diagnosis of poorly differentiated non–small cell lung cancer.
Divisions of *Pathology and Clinical Laboratory
†Thoracic Surgery, National Cancer Center Hospital, Tokyo, Japan
Supported in part by the National Cancer Center Research and Development Fund (23-A-2), (23-A-11), and (23-A-35).
The authors declare no conflict of interest.
Reprints: Koji Tsuta, MD, PhD, Division of Pathology and Clinical Laboratory, National Cancer Center Hospital, 1-1 Tsukiji 5-chome, Chuo-ku, Tokyo 104-0045, Japan (e-mail: firstname.lastname@example.org).
Received June 27, 2012
Accepted August 18, 2012