title: Gene Expression Profile of Inflammatory Myopathy with Malignancy is Similar to that of Dermatomyositis rather than Polymyositis.
abstract: Objective An association has been reported between inflammatory myopathies (IMs), which include polymyositis (PM) and dermatomyositis (DM), and malignancy, and the concept of cancer-associated myositis (CAM) was recently proposed. We herein attempted to determine the features and etiologies of these myopathies. Methods We analyzed the gene expression levels via microarray and real-time quantitative reverse transcription polymerase chain reaction analyses to identify genes that were specifically upregulated or downregulated with suspected inflammatory involvement and verified the microarray data via an immunohistochemical (IHC) analysis in additional cases. Patients We selected 14 patients with the following conditions: PM without malignancy (n=3), DM without malignancy (n=3), CAM (n=3), and Controls (no pathological changes or malignancy; n=5). Results PM was distinct from DM and CAM in a clustering analysis and exhibited the highest numbers of overexpressed genes and specific pathologies in a gene ontology analysis. The IHC analysis confirmed the gene expression results. Conclusion PM is associated with severe inflammatory pathological findings, primarily in the cell-mediated immune system. DM and CAM exhibit similarities in the gene expression and IHC results, which suggest that humoral immunity is the main etiology for both myopathies, indicating the importance of cancer screening in patients with IMs, particularly DM.
authors.affiliation: Department of Neurology, Nagoya University Graduate School of Medicine, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Noda
authors.forename: Masahiro
authors.initials: M
authors.lastname: Iijima
authors.forename: Seiya
authors.initials: S
authors.lastname: Noda
authors.forename: Shinya
authors.initials: S
authors.lastname: Maeshima
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Nakanishi
authors.forename: Seigo
authors.initials: S
authors.lastname: Kimura
authors.forename: Haruki
authors.initials: H
authors.lastname: Koike
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Ishigaki
authors.forename: Yohei
authors.initials: Y
authors.lastname: Iguchi
authors.forename: Masahisa
authors.initials: M
authors.lastname: Katsuno
authors.forename: Gen
authors.initials: G
authors.lastname: Sobue
mesh_terms: D000328:Adult; D000368:Aged; D003882:Dermatomyositis / Q000235:genetics*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D008875:Middle Aged; D009220:Myositis / Q000235:genetics*; D009369:Neoplasms / Q000235:genetics; D016133:Polymerase Chain Reaction; D017285:Polymyositis / Q000235:genetics*; D059467:Transcriptome / Q000235:genetics; D015854:Up-Regulation