title: HMGA proteins in malignant peripheral nerve sheath tumor and synovial sarcoma: preferential expression of HMGA2 in malignant peripheral nerve sheath tumor.
abstract: Histological separation of synovial sarcomas from malignant peripheral nerve sheath tumors can be difficult and available immunohistochemical markers sometimes give rise to overlapping staining patterns. Additional markers are needed to better define the two entities in the routine surgical pathology practice. To this end, we explored diagnostic applications of HMGA (HMGA1 and HMGA2) protein immunohistochemistry in comparable groups of synovial sarcoma and malignant peripheral nerve sheath tumors. The histological diagnosis of these cases was confirmed by the presence or absence of synovial sarcoma specific SYT-SSX fusion transcript analyzed by real-time reverse transcription polymerase chain reaction. In all, 13 malignant peripheral nerve sheath tumors and 15 synovial sarcomas were included in this study. Immunohistochemically, most malignant peripheral nerve sheath tumors expressed both HMGA1 and HMGA2 protein (12/13 and 12/13 cases, respectively) with moderate to strong nuclear staining patterns. Most cases of synovial sarcomas demonstrated variable expression of HMGA1. However, significant immunoreactivity for HMGA2 was present in the glandular component of a biphasic tumor (1/1) and rarely detected in monophasic synovial sarcomas (1/14). In summary, expression of HMGA2 is a feature of MPNST but not of synovial sarcoma and immunohistochemical staining of HMGA2 may be a useful marker to separate malignant peripheral nerve sheath tumor from synovial sarcoma.
authors.affiliation: Department of Pathology, Yale University School of Medicine, New Haven, CT 06520-8023, USA. pei.hui@yale.edu
authors.forename: Pei
authors.initials: P
authors.lastname: Hui
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.forename: Chaline
authors.initials: C
authors.lastname: Johnson
authors.forename: Ivo
authors.initials: I
authors.lastname: De Wever
authors.forename: Raf
authors.initials: R
authors.lastname: Sciot
authors.forename: Guidalberto
authors.initials: G
authors.lastname: Manfioletti
authors.forename: Giovanni
authors.initials: G
authors.lastname: Tallini
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis; D003937:Diagnosis, Differential; D005260:Female; D024003:HMGA Proteins / Q000096:biosynthesis*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D018317:Nerve Sheath Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D015514:Oncogene Proteins, Fusion / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013584:Sarcoma, Synovial / Q000175:diagnosis* / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D024003:HMGA Proteins; D015514:Oncogene Proteins, Fusion; C116512:SYT-SSX fusion protein