title: The prognostic impact of O6-methylguanine DNA methyltransferase and epidermal growth factor receptor expressions on primary gliosarcoma: a clinicopathologic and immunohistochemical study of seven cases at a single institution.
abstract: BACKGROUND
  Gliosarcoma is an uncommon variant of glioblastoma characterized by a biphasic tissue pattern of glial and mesenchymal differentiation. O6-methylguanine DNA methyltransferase (MGMT) is a DNA repair protein that removes mutagenic and cytotoxic adducts from O6-guanine in DNA. Lack of MGMT protein expression immunohistochemically is related to drug responses in patients of malignant glioma treated with alkylating agents. Epidermal growth factor receptor (EGFR) is the most frequently amplified gene in glioblastoma and associated with tumor invasiveness, angiogenesis, poor survival, and resistance to radiation therapy.
  
  
  OBJECTIVE
  To elucidate the relationship between the statuses of the MGMT as well as EGFR proteins and the prognosis. The study was undertaken on samples received at the Department of Pathology from 2003 to 2009.
  
  
  METHODS
  Clinicopathologic and immunohistochemical study of seven cases was performed.
  
  
  RESULTS
  This series included three men and four women with a mean age of 49.3 years at first surgery. The median progression-free survival (PFS) was 22.2 months and 8.6 months for primary tumors with 0 to 1+ and 2+ to 3+ MGMT staining, respectively; the median overall survival (OS) was 27.5 months and 14.2 months for primary tumors with 0 to 1+ and 2+ to 3+ MGMT staining, respectively. The median PFS was 17.2 months and 11.2 months for primary tumors with 0 to 1+ and 2+ to 3+ EGFR staining, respectively; the median OS was 20.4 months and 17.7 months for primary tumors with 0 to 1+ and 2+ to 3+ EGFR staining, respectively.
  
  
  CONCLUSIONS
  The series showed that MGMT and EGFR protein expressions were both unfavorable prognostic factors for patients with gliosarcoma.
authors.affiliation: Department of Pathology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Jui-Wei
authors.initials: JW
authors.lastname: Lin
authors.forename: You-Ting
authors.initials: YT
authors.lastname: Wu
authors.forename: I-Wei
authors.initials: IW
authors.lastname: Chang
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor; D015254:DNA Modification Methylases / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D045643:DNA Repair Enzymes / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D066246:ErbB Receptors / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D005260:Female; D018316:Gliosarcoma / Q000175:diagnosis* / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D025521:Tumor Suppressor Proteins / Q000032:analysis* / Q000235:genetics / Q000276:immunology
chemical_list: D014408:Biomarkers, Tumor; D025521:Tumor Suppressor Proteins; D015254:DNA Modification Methylases; C515491:MGMT protein, human; D066246:ErbB Receptors; D045643:DNA Repair Enzymes