title: The pericyte antigen RGS5 in perivascular soft tissue tumors.
abstract: Perivascular soft tissue tumors are relatively uncommon neoplasms of unclear lineage of differentiation, although most are presumed to originate from or differentiate to pericytes or a modified perivascular cell. Among these, glomus tumor, myopericytoma, and angioleiomyoma share a spectrum of histologic findings and a perivascular growth pattern. In contrast, solitary fibrous tumor was once hypothesized to have pericytic differentiation--although little bona fide evidence of pericytic differentiation exists. Likewise the perivascular epithelioid cell tumor (PEComa) family shares a perivascular growth pattern, but with distinctive dual myoid-melanocytic differentiation. RGS5, regulator of G-protein signaling 5, is a novel pericyte antigen with increasing use in animal models. Here, we describe the immunohistochemical expression patterns of RGS5 across perivascular soft tissue tumors, including glomus tumor (n = 6), malignant glomus tumor (n = 4), myopericytoma (n = 3), angioleiomyoma (n = 9), myofibroma (n = 4), solitary fibrous tumor (n = 10), and PEComa (n = 19). Immunohistochemical staining and semi-quantification was performed, and compared to αSMA (smooth muscle actin) expression. Results showed that glomus tumor (including malignant glomus tumor), myopericytoma, and angioleiomyoma shared a similar diffuse immunoreactivity for RGS5 and αSMA across all tumors examined. In contrast, myofibroma, solitary fibrous tumor and PEComa showed predominantly focal to absent RGS5 immunoreactivity. These findings further support a common pericytic lineage of differentiation in glomus tumors, myopericytoma and angioleiomyoma. The pericyte marker RGS5 may be of future clinical utility for the evaluation of pericytic differentiation in soft tissue tumors.
authors.affiliation: School of Dentistry, University of California, Los Angeles, CA, 90095.
authors.forename: Jia
authors.initials: J
authors.lastname: Shen
authors.affiliation: School of Dentistry, University of California, Los Angeles, CA, 90095; Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095.
authors.forename: Swati
authors.initials: S
authors.lastname: Shrestha
authors.affiliation: School of Dentistry, University of California, Los Angeles, CA, 90095; Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095.
authors.forename: Yu-Hsin
authors.initials: YH
authors.lastname: Yen
authors.affiliation: Nationwide Children's Hospital, Columbus, OH, 43205.
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Scott
authors.affiliation: Orthopedic Hospital Research Center, University of California, Los Angeles, CA, 90095; Department of Surgery, University of California, Los Angeles, Los Angeles, CA, 90095.
authors.forename: Chia
authors.initials: C
authors.lastname: Soo
authors.affiliation: School of Dentistry, University of California, Los Angeles, CA, 90095.
authors.forename: Kang
authors.initials: K
authors.lastname: Ting
authors.affiliation: Orthopedic Hospital Research Center, University of California, Los Angeles, CA, 90095; Center for Regenerative Medicine, University of Edinburgh, Edinburgh, UK, EH16 4UU.
authors.forename: Bruno
authors.initials: B
authors.lastname: Peault
authors.affiliation: Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Dry
authors.affiliation: School of Dentistry, University of California, Los Angeles, CA, 90095; Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095; Orthopedic Hospital Research Center, University of California, Los Angeles, CA, 90095. Electronic address: Awjames@mednet.ucla.edu.
authors.forename: Aaron W
authors.initials: AW
authors.lastname: James
mesh_terms: D000199:Actins / Q000032:analysis; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018229:Angiomyoma / Q000276:immunology / Q000473:pathology; D014408:Biomarkers, Tumor / Q000032:analysis*; D002454:Cell Differentiation; D019070:Cell Lineage; D005260:Female; D005918:Glomus Tumor / Q000276:immunology / Q000473:pathology; D006393:Hemangiopericytoma / Q000276:immunology / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D047708:Myofibroma / Q000276:immunology / Q000473:pathology; D020286:Pericytes / Q000276:immunology* / Q000473:pathology; D054973:Perivascular Epithelioid Cell Neoplasms / Q000276:immunology / Q000473:pathology; D020710:RGS Proteins / Q000032:analysis*; D012983:Soft Tissue Neoplasms / Q000276:immunology* / Q000473:pathology; D054364:Solitary Fibrous Tumors / Q000276:immunology / Q000473:pathology; D055815:Young Adult
chemical_list: C541116:ACTA2 protein, human; D000199:Actins; D014408:Biomarkers, Tumor; D020710:RGS Proteins; C491349:RGS5 protein, human
keywords: Angioleiomyoma; Glomus tumor; Hemangiopericytoma; Myopericytoma; Pericyte; RGS5; Solitary fibrous tumor