Contents lists available at ScienceDirect Lung Cancer journal homepage: www.elsevier.com/locate/lungcan Molecular profling of thymoma with myasthenia gravis: Risk factors of developing myasthenia gravis in thymoma patients Ming-Ching Lee a,b,1 , Tzu-Hung Hsiao c,d,e,1 , Han-Ni Chuang c , Li-Wen Lee a , Pei-Ling Chi f,g , Hui-Mei Tsai c , Chien-Lin Mao c , Chung-Ping Hsu a,h,i, * a Division of Thoracic Surgery, Department of Surgery, Taichung Veteran General Hospital, Taichung, 40705, Taiwan b Institute of Clinical Medicine, National Yang-Ming University, Taipei, 11221, Taiwan c Department of Medical Research, Taichung Veterans General Hospital, Taichung 40705, Taiwan d Department of Public Health, Fu Jen Catholic University, New Taipei City, 24205, Taiwan e Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung, 40227, Taiwan f Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, 81362, Taiwan g Department of Pathology and Laboratory Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, 81362, Taiwan h School of Medicine, Tzu Chi University, Hualien 77002, Taiwan i Division of Thorcic Surgery, Department of Surgery, Buddist Tzu Chi Hospital, Hualien, 97002, Taiwan ARTICLE INFO Keywords: Thymoma Myasthenia gravis HIF3A ABSTRACT Objective: Thymoma is a rare epithelial tumor arising from the thymus in the anterior mediastinum. Nearly 50% of patients with thymoma develop myasthenia gravis, which is an indication of a poor long-term prognosis. Here, we identifed specifc and efective molecular markers for predicting in the development of myasthenia gravis patients with thymoma. Material and methods: We investigated molecular profling based on RNA-sequencing (RNA-seq) for myasthenia gravis development in patients with thymoma. RNA was extracted from 34 patients with thymoma, 16 of whom had myasthenic and 18 of whom did not, and transcriptome profles were analyzed through next-generation sequencing. Results: We discovered 140 diferential expressed genes associated with myasthenia gravis in thymoma patients. The four genes, hypoxia-inducible factor 3 alpha (HIF3A), insulin-like growth factor-binding protein 1, pyruvate dehydrogenase kinase, and Krüppel-like factor 15 were diferentially expressed in patients with thymoma who has myasthenia gravis and were validated by quantitative polymerase chain reaction. HIF3A expression was signifcantly higher in patients with myasthenia gravis than in those without. Conclusion: HIF3A is aberrantly expressed in patient with thymoma who has myasthenia gravis and may be involved in the development of myasthenia gravis in thymoma patient. 1. Introduction Thymoma and thymic carcinoma are rare thymic epithelial tumors (TETs) comprising only approximately 1 % of all malignancies [1]; they can be aggressive and refractory to conventional treatment. Thymoma is a neoplasm from thymic epithelial tissue. Most cases were diagnosed at early stage and can be removed surgically [2]. Thymomas, composed of neoplasm from thymic epithelial tissue, contain numerous immature T-cells and are associated with autoimmune diseases. In healthy thymus tissue, thymic epithelial cells are involved in T-cell development and selection [3]. The World Health Organization (WHO) classifes, TETs according to their histological features including the morphology of thymic epithelial cells and number of T lymphocytes [4]. Specifcally, TETs are divided into types A, B, AB mixed, and C (or thymic https://doi.org/10.1016/j.lungcan.2019.11.007 Received 6 August 2019; Received in revised form 19 October 2019; Accepted 13 November 2019 Abbreviations: TET, thymic epithelial tumor; MG, myasthenia gravis; WHO, World Health Organization; A, hypoxia-inducible factors 3 alpha; IGFBP1, insulin-like growth factor-binding protein 1; KLF15, Krüppel-like factor 15; PDK4, pyruvate dehydrogenase kinase 4; PCA, principal components analysis; IGF, insulin growth factor; AUC, area under the curve; AIRE, autoimmune regulator; TCVGH, Taichung Veterans General Hospital; DAVID, database for annotation, visualization and integrated discovery ⁎ Corresponding author at: Division of Thoracic Surgery, Department of Surgery, Buddhist Tzu Chi Hospital, Hualien, 97002, Taiwan. E-mail address: clifhsu@gmail.com (C.-P. Hsu). 1 These authors contributed equally to this work. Lung Cancer 139 (2020) 157–164 0169-5002/ © 2019 Elsevier B.V. All rights reserved. T