title: Immunohistochemical analysis of O6-methylguanine-DNA methyltransferase (MGMT) protein expression as prognostic marker in glioblastoma patients treated with radiation therapy with concomitant and adjuvant Temozolomide.
abstract: BACKGROUND
  O6-methylguanine-DNA methyltransferase (MGMT) protein expression using immunohistochemical analysis was proposed as a prognostic marker for patients with newly diagnosed glioblastoma (GBM) treated with radiation therapy with concurrent and adjuvant Temozolomide (TMZ).
  
  
  METHODS
  From April 2012 to October 2014, 73 patients with newly diagnosed GBM, MGMT protein expression were analyzed in formalin-fixed, paraffin-embedded tumor specimens. Patients received the radiation therapy plus concomitant and adjuvant TMZ chemotherapy.
  
  
  RESULTS
  For the whole cohort, the median overall survival (OS) was 15 months, and the progression-free survival was 10 months. Patients who had low MGMT protein expression (⩽15%) had a significantly improved OS and PFS compared with patients who had high MGMT expression (17.0 months vs 14 months; P value .006) and (15.0 months vs 10 months; P value .016) respectively. The age and extent of tumor resection were the strongest clinical predictors of outcome. In multivariate Cox models MGMT protein expression, extent of tumor resection and age were identified as independent prognostic factors.
  
  
  CONCLUSIONS
  MGMT expression was identified as positive prognostic factor in patients with newly diagnosed glioblastoma who underwent surgical resection followed by adjuvant radiotherapy and concomitant oral TMZ chemotherapy (the Stupp protocol).
authors.affiliation: Clininal Oncology Department, Faculty of Medicine, Tanta University, Tanta, Egypt.
authors.forename: Samar Galal
authors.initials: SG
authors.lastname: Younis
authors.affiliation: Clininal Oncology Department, Faculty of Medicine, Tanta University, Tanta, Egypt. Electronic address: Khedr_rasha@yahoo.com.
authors.forename: Rasha Abd El-Ghany
authors.initials: RA
authors.lastname: Khedr
authors.affiliation: Histopathology Department, Faculty of Medicine, Tanta University, Tanta, Egypt.
authors.forename: Safinaz Hamdy
authors.initials: SH
authors.lastname: El-Shorbagy
mesh_terms: D000328:Adult; D000368:Aged; D018906:Antineoplastic Agents, Alkylating / Q000627:therapeutic use; D014408:Biomarkers, Tumor; D001932:Brain Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000401:mortality / Q000628:therapy*; D017024:Chemotherapy, Adjuvant; D003131:Combined Modality Therapy; D003606:Dacarbazine / Q000031:analogs & derivatives / Q000627:therapeutic use; D005260:Female; D015870:Gene Expression; D005909:Glioblastoma / Q000235:genetics / Q000378:metabolism* / Q000401:mortality / Q000628:therapy*; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D019853:O(6)-Methylguanine-DNA Methyltransferase / Q000235:genetics / Q000378:metabolism*; D011379:Prognosis; D018714:Radiotherapy, Adjuvant; D000077204:Temozolomide; D016896:Treatment Outcome
chemical_list: D018906:Antineoplastic Agents, Alkylating; D014408:Biomarkers, Tumor; D003606:Dacarbazine; D019853:O(6)-Methylguanine-DNA Methyltransferase; D000077204:Temozolomide
keywords: Glioblastoma; Immunohistochemistry; O6-methylguanine-DNA methyltransferase; Temozolomide