title: Activating transcription factor 2 in mesenchymal tumors.
abstract: Activating transcription factor 2 (ATF2) is a member of activator protein 1 superfamily, which can heterodimerize with other transcription factors regulating cell differentiation and survival. ATF2 assembles into a complex with the synovial sarcoma translocation, chromosome 18 (SS18)-synovial sarcoma, X breakpoint (SSX) fusion oncoprotein, and the transducin-like enhancer of split 1 (TLE1) corepressor, driving oncogenesis in synovial sarcoma. The fusion oncoproteins in many other translocation-associated sarcomas incorporate transcription factors from the ATF/cAMP response element binding or E26 families, which potentially form heterodimers with ATF2 to regulate transcription. ATF2 may therefore play an important role in the oncogenesis of many mesenchymal tumors, but as yet, little is known about its protein expression in patient specimens. Herein we perform immunohistochemical analyses using a validated specific antibody for ATF2 expression and intracellular localization on a cohort of 594 malignant and 207 benign mesenchymal tumors representing 47 diagnostic entities. Melanoma served as a positive control for nuclear and cytoplasmic staining. High nuclear ATF2 expression was mainly observed in translocation-associated and/or spindle cell sarcomas including synovial sarcoma, desmoplastic small round cell tumor, endometrial stromal sarcoma, gastrointestinal stromal tumor, malignant peripheral nerve sheath tumor, and solitary fibrous tumor. Cytoplasmic ATF2 expression was less frequently seen than nuclear expression in malignant mesenchymal tumors. Benign mesenchymal tumors mostly showed much lower nuclear and cytoplasmic ATF2 expression.
authors.affiliation: Genetic Pathology Evaluation Centre, University of British Columbia, Vancouver, British Columbia, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Department of Anatomic Pathology, Kyushu University, Fukuoka, Japan; Department of Orthopaedic Surgery, Kyushu University, Fukuoka, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Endo
authors.affiliation: Biomedical Research Centre, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Le
authors.initials: L
authors.lastname: Su
authors.affiliation: Genetic Pathology Evaluation Centre, University of British Columbia, Vancouver, British Columbia, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada. Electronic address: torsten@mail.ubc.ca.
authors.forename: Torsten O
authors.initials: TO
authors.lastname: Nielsen
mesh_terms: D051698:Activating Transcription Factor 2 / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D018204:Neoplasms, Connective and Soft Tissue / Q000235:genetics / Q000378:metabolism*; D013584:Sarcoma, Synovial / Q000235:genetics / Q000378:metabolism; D046888:Tissue Array Analysis
chemical_list: C497105:ATF2 protein, human; D051698:Activating Transcription Factor 2
keywords: Activating transcription factor 2; Immunohistochemistry; Mesenchymal tumor; Transcription factor; Translocation-associated sarcoma