title: Comparison of promoter hypermethylation pattern in salivary rinses collected with and without an exfoliating brush from patients with HNSCC.
abstract: BACKGROUND
  Salivary rinses have been recently proposed as a valuable resource for the development of epigenetic biomarkers for detection and monitoring of head and neck squamous cell carcinoma (HNSCC). Both salivary rinses collected with and without an exfoliating brush from patients with HNSCC are used in detection of promoter hypermethylation, yet their correlation of promoter hypermethylation has not been evaluated. This study was to evaluate the concordance of promoter hypermethylation between salivary rinses collected with and without an exfoliating brush from patients with HNSCC. METHODOLGY: 57 paired salivary rinses collected with or without an exfoliating brush from identical HNSCC patients were evaluated for promoter hypermethylation status using Quantitative Methylation-Specific PCR. Target tumor suppressor gene promoter regions were selected based on our previous studies describing a panel for HNSCC screening and surveillance, including P16, CCNA1, DCC, TIMP3, MGMT, DAPK and MINT31.
  
  
  RESULTS
  In salivary rinses collected with and without brush, frequent methylation was detected in P16 (8.8% vs. 5.2%), CCNA1 (26.3% vs. 22.8%), DCC (33.3% vs. 29.8%), TIMP3 (31.6% vs. 36.8%), MGMT (29.8% vs. 38.6%), DAPK (14.0% vs. 19.2%), and MINT31 (10.5% vs. 8.8%). Spearman's rank correlation coefficient showed a positive correlation between salivary rinses collected with and without brush for P16 (ρ = 0.79), CCNA1 (ρ = 0.61), DCC (ρ = 0.58), TIMP3 (ρ = 0.10), MGMT (ρ = 0.70), DAPK (ρ = 0.51) and MINT31 (ρ = 0.72) (P<0.01). The percent agreement of promoter methylation between salivary rinses with brush and without brush were 96.5% for P16, 82.5% for CCNA1, 78.9% for DCC, 59.7% for TIMP3, 84.2% for MGMT, 84.2% for DAPK, and 94.7% for MINT31.
  
  
  CONCLUSIONS
  Our study demonstrated strong correlations of gene promoter hypermethylation between salivary rinses collected with and without an exfoliating brush. Salivary rinse collection without using an exfoliating brush may offer a cost effective, rapid, non-invasive, and reliable means for development of epigenetic salivary rinse biomarkers.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Johns Hopkins Medical Institutions, Baltimore, Maryland, United States of America.
authors.forename: Wenyue
authors.initials: W
authors.lastname: Sun
authors.forename: David
authors.initials: D
authors.lastname: Zaboli
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.forename: Demetri
authors.initials: D
authors.lastname: Arnaoutakis
authors.forename: Tanbir
authors.initials: T
authors.lastname: Khan
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Wayne
authors.initials: W
authors.lastname: Koch
authors.forename: Zubair
authors.initials: Z
authors.lastname: Khan
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Califano
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D051017:Apoptosis Regulatory Proteins / Q000235:genetics; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics; D002294:Carcinoma, Squamous Cell / Q000235:genetics*; D056750:Cyclin A1 / Q000235:genetics; D019175:DNA Methylation; D015254:DNA Modification Methylases / Q000235:genetics; D045643:DNA Repair Enzymes / Q000235:genetics; D004273:DNA, Neoplasm / Q000235:genetics* / Q000302:isolation & purification*; D064550:Death-Associated Protein Kinases; D044127:Epigenesis, Genetic; D005260:Female; D016163:Genes, DCC; D019942:Genes, p16; D006258:Head and Neck Neoplasms / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011401:Promoter Regions, Genetic; D012463:Saliva / Q000737:chemistry* / Q000166:cytology; D019717:Tissue Inhibitor of Metalloproteinase-3 / Q000235:genetics; D025521:Tumor Suppressor Proteins / Q000235:genetics
chemical_list: D051017:Apoptosis Regulatory Proteins; C503745:CCNA1 protein, human; D056750:Cyclin A1; D004273:DNA, Neoplasm; D019717:Tissue Inhibitor of Metalloproteinase-3; D025521:Tumor Suppressor Proteins; D015254:DNA Modification Methylases; C515491:MGMT protein, human; D064550:Death-Associated Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D045643:DNA Repair Enzymes