title: Identification of methylation markers for the prediction of nodal metastasis in oral and oropharyngeal squamous cell carcinoma.
abstract: Hypermethylation is an important mechanism for the dynamic regulation of gene expression, necessary for metastasizing tumour cells. Our aim is to identify methylation tumour markers that have a predictive value for the presence of regional lymph node metastases in patients with oral and oropharyngeal squamous cell carcinoma (OOSCC). Significantly differentially expressed genes were retrieved from four reported microarray expression profiles comparing pN0 and pN+ head-neck tumours, and one expression array identifying functionally hypermethylated genes. Additional metastasis-associated genes were included from the literature. Thus genes were selected that influence the development of nodal metastases and might be regulated by methylation. Methylation-specific PCR (MSP) primers were designed and tested on 8 head-neck squamous cell carcinoma cell lines and technically validated on 10 formalin-fixed paraffin-embedded (FFPE) OOSCC cases. Predictive value was assessed in a clinical series of 70 FFPE OOSCC with pathologically determined nodal status. Five out of 28 methylation markers (OCLN, CDKN2A, MGMT, MLH1 and DAPK1) were frequently differentially methylated in OOSCC. Of these, MGMT methylation was associated with pN0 status (P = 0.02) and with lower immunoexpression (P = 0.02). DAPK1 methylation was associated with pN+ status (P = 0.008) but did not associate with protein expression. In conclusion, out of 28 candidate genes, two (7%) showed a predictive value for the pN status. Both genes, DAPK1 and MGMT, have predictive value for nodal metastasis in a clinical group of OOSCC. Therefore DNA methylation markers are capable of contributing to diagnosis and treatment selection in OOSCC. To efficiently identify additional new methylation markers, genome-wide methods are needed.
authors.affiliation: a Dept. of Oral & Maxillofacial Surgery ; University of Groningen; University Medical Center Groningen ; Groningen , The Netherlands.
authors.forename: L J
authors.initials: LJ
authors.lastname: Melchers
authors.forename: M J A M
authors.initials: MJ
authors.lastname: Clausen
authors.forename: M F
authors.initials: MF
authors.lastname: Mastik
authors.forename: L
authors.initials: L
authors.lastname: Slagter-Menkema
authors.forename: J E
authors.initials: JE
authors.lastname: van der Wal
authors.forename: G B A
authors.initials: GB
authors.lastname: Wisman
authors.forename: J L N
authors.initials: JL
authors.lastname: Roodenburg
authors.forename: E
authors.initials: E
authors.lastname: Schuuring
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D019175:DNA Methylation; D015254:DNA Modification Methylases / Q000235:genetics* / Q000378:metabolism; D045643:DNA Repair Enzymes / Q000235:genetics* / Q000378:metabolism; D064550:Death-Associated Protein Kinases / Q000235:genetics* / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D009959:Oropharyngeal Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D011237:Predictive Value of Tests; D012307:Risk Factors; D012680:Sensitivity and Specificity; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D025521:Tumor Suppressor Proteins; D015254:DNA Modification Methylases; C515491:MGMT protein, human; C579096:DAPK1 protein, human; D064550:Death-Associated Protein Kinases; D045643:DNA Repair Enzymes
keywords: DAPK1; MGMT; biomarker; expression; head and neck cancer; lymph node metastasis; methylation; oral cancer