title: [Biomarkers in high-grade gliomas: A systematic review].
abstract: BACKGROUND
  Biomarkers are a subcategory of clinical signs that can be measured and reproduced with precision and influence to predict outcome. Tissue, cells, and fluid conform the biological process. Biomarker usefulness is to determine and specify illness predisposition counting with variability and validity. Process systematization can reduce operative costs. To date, four major biomarkers have been described for high-grade gliomas: 1p/19q deletion, O6-methylguanine-DNA methyltransferase (MGMT) promoter mutation, IDH1/IDH2 mutation, and microRNA. In this manuscript we present a systematic review according to the MOOSE protocol to establish the bases to describe the utility of biomarkers in high-grade tumors.
  
  
  METHODS
  We conducted a systematic review of the literature according to the PRISMA and MOOSE guides of all the published data from January 2004 to November 2014 with the key words: "biological markers" and "glioblastoma" that included OR and 95% CI. One researcher performed data extraction and analysis.
  
  
  RESULTS
  A total of 169 articles were found in three major medical search engines: PubMed (42), Embase (30) and Ovid (96).
  
  
  CONCLUSIONS
  Biomarkers are tools designed for early detection of specific illnesses such as high-grade glioma. Lack of methodological standardization slows down the speed of progress.
authors.affiliation: Departamento de Neurocirugía, Centro Médico ABC Observatorio, México, D.F., México.
authors.forename: Salvador
authors.initials: S
authors.lastname: Manrique-Guzmán
mesh_terms: D005819:Genetic Markers; D005910:Glioma / Q000235:genetics* / Q000473:pathology*; D006801:Humans; D060787:Neoplasm Grading
chemical_list: D005819:Genetic Markers