title: Immunohistochemical and molecular detection of the expression of FGF23 in phosphaturic mesenchymal tumors including the non-phosphaturic variant.
abstract: BACKGROUND
  Phosphaturic mesenchymal tumors (PMTs) are rare neoplasms that are often associated with tumor-induced osteomalacia (TIO) due to excessive serum levels of fibroblast growth factor 23 (FGF23). PMTs share overlapping histologic features with other types of tumors; thus, accurate pathological diagnosis may be challenging. We performed an immunohistochemical examination of FGF23 expression in PMTs and other types of tumors, together with pertinent molecular analyses.
  
  
  METHODS
  Seven PMTs (5 with TIO and 2 without TIO) and 46 other types of bone and soft tissue tumors were retrieved, and immunohistochemistry was performed using a commercially available anti-FGF23 antibody. In addition, FGF23 mRNA expression was detected by reverse transcription-polymerase chain reaction (RT-PCR), using RNA extracted from formalin-fixed, paraffin-embedded tissues.
  
  
  RESULTS
  Immunohistochemical analysis of FGF23 expression showed distinct, punctate staining in the cytoplasm in 5 PMTs with TIO, whereas FGF23 expression was negative in the 2 PMTs without TIO and the other 46 tumors. FGF23 mRNA expression was detected in all 4 PMTs examined, as well as in 1 chondromyxoid fibroma and 1 myxoid liposarcoma. The real-time RT-PCR data showed that the relative expression levels of the FGF23 mRNA tended to be higher in PMTs with TIO than in PMTs without TIO, or in the chondromyxoid fibroma specimen.
  
  
  CONCLUSIONS
  Our data suggested that the feasibility of immunohistochemical detection of FGF23 may depend on the level of secreted FGF23 from tumor cells. Thus, immunohistochemistry for FGF23 is an useful diagnostic adjunct for PMT, although its utility appears to be limited in cases without TIO.
authors.affiliation: Department of Pathology and Oncology, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555, Japan. e-shiba@clnc.uoeh-u.ac.jp.
authors.forename: Eisuke
authors.initials: E
authors.lastname: Shiba
authors.affiliation: Department of Pathology and Oncology, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555, Japan. amatsu@med.uoeh-u.ac.jp.
authors.forename: Atsuji
authors.initials: A
authors.lastname: Matsuyama
authors.affiliation: Department of Pathology and Oncology, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555, Japan. r.shibusan@gmail.com.
authors.forename: Ryo
authors.initials: R
authors.lastname: Shibuya
authors.affiliation: Department of Pathology and Oncology, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555, Japan. kei_0406_talbo_zaurus_y_6432@yahoo.co.jp.
authors.forename: Kei
authors.initials: K
authors.lastname: Yabuki
authors.affiliation: Department of Pathology and Oncology, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555, Japan. suigetsuisya@yahoo.co.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Harada
authors.affiliation: Kagoshima Occupational and Environmental Health Center, 4-96 Tokaicho, Kagoshima, 891-0115, Japan. n_roice@yahoo.co.jp.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Nakamoto
authors.affiliation: National Hospital Organization Kinki-Chuo Chest Medical Center, 1180 Nagasonecho, Kita-ku, Sakai, Osaka, 591-8025, Japan. takasaikahiko@icloud.com.
authors.forename: Takahiko
authors.initials: T
authors.lastname: Kasai
authors.affiliation: Department of Pathology and Oncology, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555, Japan. hisaoka@med.uoeh-u.ac.jp.
authors.forename: Masanori
authors.initials: M
authors.lastname: Hisaoka
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis* / Q000235:genetics; D003937:Diagnosis, Differential; D005240:Feasibility Studies; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000032:analysis* / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009372:Neoplasms, Connective Tissue / Q000737:chemistry* / Q000235:genetics / Q000473:pathology; D010018:Osteomalacia; D010257:Paraneoplastic Syndromes; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; C000717427:FGF23 protein, human; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23