Expression of tropomyosins in lung cancer - a potential role in carcinogenesis and its utility in a histopathological diagnosis

Koji Okudela¹, Hideaki Mitsui¹, Tetsukan Woo², Yoko Kojima^1,2, Mai Matsumura¹, Hiromasa Arai³, Takehisa Suzuki¹, Shigeaki Umeda¹, Yoko Tateishi¹, Yuichi Saito¹, Michihiko Tajiri³, Munetaka Masuda², Yoichi Kameda⁴ and Kenichi Ohashi¹

Department of ¹Pathology and ²Surgery, Yokohama City University Graduate School of Medicine, Kanazawa-ku, Yokohama, Japan and ³Division of General Thoracic Surgery and ⁴Pathology, Kanagawa Prefectural Cardiovascular and Respiratory Center Hospital, Tomioka-higashi, Kanazawa-ku, Yokohama, Japan

Offprint requests to: Koji Okudela, Department of Pathology, Yokohama City University Graduate School of Medicine, 3-9, Future, Kanazawa-ku, 236-0004, Yokohama, Japan. e-mail: kojixok@yokohama-cu.ac.jp

Summary. We herein analyzed the relationships between tropomyosin protein expression levels and clinicopathological factors in order to determine the significance of tropomyosins in lung cancers. Although neoplastic cells expressed different isoforms of tropomyosin, overall expression levels were lower than those in bronchial and alveolar epithelial cells. In adenocarcinomas, tropomyosin levels were markedly reduced in poorly differentiated or solid subtype carcinomas, suggesting that a loss in the expression of tropomyosins is involved in the progression of lung adenocarcinomas. The potential utility of the immuno-histochemical expression of tropomyosins for a histopathological diagnosis was also investigated. The sensitivity and specificity of a loss in the expression of tropomyosins were 100% and 50%, respectively, which were superior to those for the strong expression of p53 (sensitivity 100% and specificity 44%), a conventional biomarker. An immunohistochemical examination of tropomyosins may assist in the histopathological detection of lung cancer cells in small biopsy specimens. Histol Histopathol 31, 857-866 (2016)

Key words: Tropomyosin, Lung cancer, Carcinogenesis, Biomarker

DOI: 10.14670/HH-11-721