title: Epigenetic markers for early detection of nasopharyngeal carcinoma in a high risk population.
abstract: BACKGROUND
  Undifferentiated nasopharyngeal carcinoma (NPC) is strongly related to Epstein-Barr virus (EBV) infection, allowing aberrant antibodies against EBV and viral DNA load as screening tools in high risk populations. Methylation analysis in the promoter of tumor suppressor genes (TSGs) may serve as a complementary marker for identifying early cases. This study determined methylation status of multiple TSGs and evaluated whether it may improve early detection.
  
  
  METHODS
  Nasopharyngeal brushings were taken from 53 NPC patients, 22 high risk subjects and 25 healthy EBV carriers. Corresponding NPC paraffin tissue was included. DNA was bisulfite-modified preceding analysis by methylation-specific PCR (MSP). Ten TSGs were studied.
  
  
  RESULTS
  NPC paraffin and brushing DNA revealed an 81.8% concordance so that MSP analysis was done using either one of both specimens. NPC samples showed methylation for individual TSGs (DAPK1 79.2%, CDH13 77.4%, DLC1 76.9%, RASSF1A 75.5%, CADM1 69.8%, p16 66.0%, WIF1 61.2%, CHFR 58.5%, RIZ1 56.6% and RASSF2A 29.2%). High risk individuals, having elevated EBV IgA and viral load, showed high frequency of methylation of CDH13, DAPK1, DLC1 and CADM1, but low frequency of methylation of p16 and WIF1 and undetectable methylation of RASSF1A, CHFR, RIZ1 and RASSF2A. Healthy subjects showed similar patterns as high risk individuals. A combination of RASSF1A and p16 gave good discrimination between NPC and non-NPC, but best results were combined analysis of five methylation markers (RASSF1A, p16, WIF1, CHFR and RIZ1) with detection rate of 98%.
  
  
  CONCLUSIONS
  Multiple marker MSP is proposed as a complementary test for NPC risk assessment in combination with EBV-based markers.
authors.affiliation: Faculty of Medicine/Dr Sardjito Hospital, Universitas Gadjah Mada,Yogyakarta, Indonesia.
authors.forename: Susanna H
authors.initials: SH
authors.lastname: Hutajulu
authors.forename: Sagung R
authors.initials: SR
authors.lastname: Indrasari
authors.forename: Luh P L
authors.initials: LP
authors.lastname: Indrawati
authors.forename: Ahmad
authors.initials: A
authors.lastname: Harijadi
authors.forename: Sylvia
authors.initials: S
authors.lastname: Duin
authors.forename: Sofia M
authors.initials: SM
authors.lastname: Haryana
authors.forename: Renske D M
authors.initials: RD
authors.lastname: Steenbergen
authors.forename: Astrid E
authors.initials: AE
authors.lastname: Greijer
authors.forename: Jaap M
authors.initials: JM
authors.lastname: Middeldorp
mesh_terms: D000914:Antibodies, Viral / Q000276:immunology; D014408:Biomarkers, Tumor / Q000235:genetics*; D002277:Carcinoma; D019175:DNA Methylation; D004279:DNA, Viral / Q000235:genetics; D057890:Epigenomics; D020031:Epstein-Barr Virus Infections / Q000276:immunology; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000276:immunology; D006801:Humans; D007070:Immunoglobulin A / Q000276:immunology; D026901:Membrane Transport Proteins / Q000235:genetics; D009185:Myelin Proteins / Q000235:genetics; D062806:Myelin and Lymphocyte-Associated Proteolipid Proteins; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000175:diagnosis* / Q000821:virology; D011401:Promoter Regions, Genetic / Q000235:genetics; D011510:Proteolipids / Q000235:genetics; D025521:Tumor Suppressor Proteins / Q000235:genetics
chemical_list: D000914:Antibodies, Viral; D014408:Biomarkers, Tumor; D004279:DNA, Viral; D007070:Immunoglobulin A; C569026:MAL protein, human; D026901:Membrane Transport Proteins; D009185:Myelin Proteins; D062806:Myelin and Lymphocyte-Associated Proteolipid Proteins; D011510:Proteolipids; D025521:Tumor Suppressor Proteins