title: Hepatic carcinosarcoma: evidence of polyclonal origin based on microsatellite analysis.
abstract: OBJECTIVE
  Hepatic carcinosarcoma (HCS) is an aggressive tumor for which a consensus regarding the clonal origin has not yet been reached. The aim of the study was to identify the origin of the hepatocellular carcinoma (HCC) and sarcoma components in HCS.
  
  
  METHODS
  We chose microsatellite technique containing loss of heterozygosity (LOH) and microsatellite instability (MSI) on three HCS patients who underwent curative resection confirmed by pathological examination. Tumors were firstly analyzed for Hep Par 1, CK18, CD10, CD117, SMA and vimentin expression by immunohistochemistry. LOH and MSI were then investigated. The incidence rate of LOH/MSI in all nine MS was calculated as the fractional allelic loss (FAL) index, which was internationally recognized standard. A FAL<30% was representative of a monoclonal origin and a FAL≥30% indicated a polyclonal origin.
  
  
  RESULTS
  All patients were positive for HBsAg. Microscopic examination showed HCS containing two different cell types: a fibrosarcoma component with spindle cells and an HCC population of cells with a trabecular pattern. In the HCC tumor portions, Hep Par 1, CK18, CD10 were expressed while vimentin was not. In contrast, the spindle cell populations were positive for vimentin and negative for Hep Par 1, CK18, CD10. The highest frequencies of LOH and MSI were at the D16S505 (2/3; 66.7%), D17S831 (2/3; 66.7%) and D17S938 MS (2/3; 66.7%). The FALs for the three cases of HCS were 50% (4/8), 55.6% (5/9) and 33.3% (3/9), suggesting a polyclonal origin.
  
  
  CONCLUSIONS
  Immunohistochemistry and analysis of LOH and MSI strongly demonstrated that the three HCS samples were consistent with a polyclonal origin for all three cases.
authors.affiliation: Department of Pathology, Eastern Hepatobiliary Surgery Hospital, The Second Military Medical University, Shanghai, China.
authors.forename: Yi-Jin
authors.initials: YJ
authors.lastname: Gu
authors.affiliation: Department of Pathology, Eastern Hepatobiliary Surgery Hospital, The Second Military Medical University, Shanghai, China.
authors.forename: Yu-Yao
authors.initials: YY
authors.lastname: Zhu
authors.affiliation: Department of Pathology, Eastern Hepatobiliary Surgery Hospital, The Second Military Medical University, Shanghai, China.
authors.forename: Xin-Yuan
authors.initials: XY
authors.lastname: Lu
authors.affiliation: Department of Pathology, Eastern Hepatobiliary Surgery Hospital, The Second Military Medical University, Shanghai, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhao
authors.affiliation: Department of Pathology, Eastern Hepatobiliary Surgery Hospital, The Second Military Medical University, Shanghai, China. Electronic address: wmcong@smmu.edu.cn.
authors.forename: Wen-Ming
authors.initials: WM
authors.lastname: Cong
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D002296:Carcinosarcoma / Q000235:genetics* / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000235:genetics* / Q000473:pathology*; D019656:Loss of Heterozygosity; D008297:Male; D042282:Microdissection; D053842:Microsatellite Instability; D008875:Middle Aged; D018807:Polymorphism, Single-Stranded Conformational; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D014408:Biomarkers, Tumor
keywords: Clonal origin; Hepatic carcinosarcoma; Loss of heterozygosity; Microsatellite; Microsatellite instability