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Significant Expression of Thyroid Transcription Factor-1 in Pulmonary Squamous Cell Carcinoma Detected by SPT24 Monoclonal Antibody and CSA-II System

Kashima, Kenji MD, PhD*; Hashimoto, Hisashi*; Nishida, Haruto MD*; Arakane, Motoki MD*; Yada, Naomi DDS, PhD; Daa, Tsutomu MD, PhD*; Yokoyama, Shigeo MD, PhD*

Applied Immunohistochemistry & Molecular Morphology: February 2014 - Volume 22 - Issue 2 - p 119–124
doi: 10.1097/PAI.0b013e31828acad2
Research Articles

In contrast to the usefulness of thyroid transcription factor-1 (TTF-1) in distinguishing primary adenocarcinoma of the lung from metastatic lesions, TTF-1 expression in pulmonary squamous cell carcinoma is reported to be at low level and not a suitable immunohistochemical marker. We hypothesized that the highly sensitive detection system, CSA-II, can visualize even faint expression of TTF-1 in pulmonary squamous cell carcinoma. In this study, 2 commercially available clones of TTF-1 monoclonal antibody, 8G7G3/1 and SPT24, were used for staining 38 cases of pulmonary squamous cell carcinoma, in combination with the CSA-II and the conventional detection system, EnVision. The combined use of the 8G7G3/1 clone with EnVision and CSA-II showed a positive reaction in only 1 and 4 cases, respectively. The use of SPT24 clone showed positive staining in 5 cases with EnVision and in 20 of 38 cases (52.6%) with the CSA-II. Interestingly, positive staining by the SPT24-CSA-II technique of samples from tissue blocks preserved for <2 years was 73.6% compared with only 31.5% in those preserved for >2 years. In addition, a 6-month preservation of the cut sections resulted in stain fading and decreased positivity (50%), compared with freshly cut sections. We conclude that the use of the SPT24 monoclonal antibody with the CSA-II system can detect even weak expression of TTF-1 in pulmonary squamous cell carcinoma. This staining technique can potentially allow the discrimination of primary squamous cell carcinoma of the lung from metastatic lesions, especially in freshly prepared paraffin sections.

*Department of Diagnostic Pathology, Faculty of Medicine, Oita University, Yufu, Oita

Department of Bioscience, Division of Oral Pathology, Kyushu Dental College, Kitakyushu, Japan

The authors declare no conflict of interest.

Reprints: Kenji Kashima, MD, PhD, Department of Diagnostic Pathology, Faculty of Medicine, Oita University, Hasama-machi, Yufu, Oita 879-5593, Japan (e-mail: kkashima@oita-u.ac.jp).

Received December 12, 2012

Accepted January 30, 2013

© 2014 Lippincott Williams & Wilkins, Inc.