title: Pericytic mimicry in well-differentiated liposarcoma/atypical lipomatous tumor.
abstract: Pericytes are modified smooth muscle cells that closely enwrap small blood vessels, regulating and supporting the microvasculature through direct endothelial contact. Pericytes demonstrate a distinct immunohistochemical profile, including expression of smooth muscle actin, CD146, platelet-derived growth factor receptor β, and regulator of G-protein signaling 5. Previously, pericyte-related antigens have been observed to be present among a group of soft tissue tumors with a perivascular growth pattern, including glomus tumor, myopericytoma, and angioleiomyoma. Similarly, malignant tumor cells have been shown to have a pericyte-like immunoprofile when present in a perivascular location, seen in malignant melanoma, glioblastoma, and adenocarcinoma. Here, we examine well-differentiated liposarcoma specimens, which showed some element of perivascular areas with the appearance of smooth muscle (n = 7 tumors). Immunohistochemical staining was performed for pericyte antigens, including smooth muscle actin, CD146, platelet-derived growth factor receptor β, and regulator of G-protein signaling 5. Results showed consistent pericytic marker expression among liposarcoma tumor cells within a perivascular distribution. MDM2 immunohistochemistry and fluorescence in situ hybridization for MDM2 revealed that these perivascular cells were of tumor origin (7/7 tumors), whereas double immunohistochemical detection for CD31/CD146 ruled out an endothelial cell contribution. These findings further support the concept of pericytic mimicry, already established in diverse malignancies, and its presence in well-differentiated liposarcoma. The extent to which pericytic mimicry has prognostic significance in liposarcoma is as yet unknown.
authors.affiliation: School of Dentistry, University of California, Los Angeles, CA 90095.
authors.forename: Jia
authors.initials: J
authors.lastname: Shen
authors.affiliation: 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: Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095.
authors.forename: P Nagesh
authors.initials: PN
authors.lastname: Rao
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: Greg
authors.initials: G
authors.lastname: Asatrian
authors.affiliation: Nationwide Children's Hospital, Columbus, OH 43205.
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Scott
authors.affiliation: Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095.
authors.forename: Vi
authors.initials: V
authors.lastname: Nguyen
authors.affiliation: Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095.
authors.forename: Paulina
authors.initials: P
authors.lastname: Giacomelli
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: Department of Surgery, University of California, Los Angeles, Los Angeles, CA 90095.
authors.forename: Fritz C
authors.initials: FC
authors.lastname: Eilber
authors.affiliation: Orthopedic Hospital Research Center, University of California, Los Angeles, CA 90095; Center for Regenerative Medicine, University of Edinburgh, Edinburgh, United Kingdom.
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; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D001706:Biopsy; D051929:CD146 Antigen / Q000032:analysis; D002454:Cell Differentiation; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008067:Lipoma / Q000737:chemistry / Q000235:genetics / Q000473:pathology*; D008080:Liposarcoma / Q000737:chemistry / Q000235:genetics / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D018716:Molecular Mimicry; D020286:Pericytes / Q000737:chemistry / Q000473:pathology*; D010641:Phenotype; D051736:Proto-Oncogene Proteins c-mdm2 / Q000032:analysis / Q000235:genetics; D020710:RGS Proteins / Q000032:analysis; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000032:analysis; D012189:Retrospective Studies
chemical_list: C541116:ACTA2 protein, human; D000199:Actins; D014408:Biomarkers, Tumor; D051929:CD146 Antigen; C497902:MCAM protein, human; D020710:RGS Proteins; C491349:RGS5 protein, human; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2; C000605860:PDGFRB protein, human; D020797:Receptor, Platelet-Derived Growth Factor beta
keywords: CD146; Liposarcoma; PDGFRβ; Pericyte; SMA