title: Aberrant methylation and expression of DAPk1 in human hypopharyngeal squamous cell carcinoma.
abstract: CONCLUSIONS
  These findings indicate that in hypopharyngeal squamous cell carcinoma (HSCC), hypermethylation and down-regulation of death-associated protein kinase-1 (DAPk1) are common events, which are associated with a poor prognosis.
  
  
  OBJECTIVE
  This study aimed to investigate the methylation and expression of DAPk1, a tumor suppressor gene, in HSCC, and explore its clinical significance.
  
  
  METHODS
  The tumor and adjacent non-tumor tissues were collected from 53 patients with HSCC. The methylation status of DAPk1 was detected by methylation-specific polymerase chain reaction (MSP), and expression of DAPk1 was determined with real-time reverse transcriptase polymerase chain reaction (RT-PCR), immunohistochemistry, and Western blot at mRNA or protein levels. Correlations between the findings and patients' clinicopathological parameters were further evaluated.
  
  
  RESULTS
  The methylation ratio of DAPk1 in tumor tissues (60.38%) was significantly higher than that in the adjacent non-tumor tissues (26.42%) (p = 0.001), while DAPk1 expression in the tumors was down-regulated markedly (real-time RT-PCR, p = 0.002; immunohistochemistry, p = 0.006; Western blot, p < 0.001). DAPk1 methylation was negatively correlated with its mRNA expression (p = 0.002, r = -0.521). Both hypermethylation and down-regulation of DAPk1 were closely related to lymph node metastasis (p = 0.001 and 0.001, respectively), advanced TNM stage (p = 0.009 and 0.019, respectively), and low survival rates (p = 0.031 and 0.045, respectively).
authors.affiliation: Department of Otolaryngology, Qilu Hospital of Shandong University , Jinan, Shandong , China.
authors.forename: Dong-Min
authors.initials: DM
authors.lastname: Wei
authors.forename: Da-Yu
authors.initials: DY
authors.lastname: Liu
authors.forename: Da-Peng
authors.initials: DP
authors.lastname: Lei
authors.forename: Tong
authors.initials: T
authors.lastname: Jin
authors.forename: Juan
authors.initials: J
authors.lastname: Wang
authors.forename: Xin-Liang
authors.initials: XL
authors.lastname: Pan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D019175:DNA Methylation / Q000235:genetics*; D064550:Death-Associated Protein Kinases / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007012:Hypopharyngeal Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D015996:Survival Rate
chemical_list: D012333:RNA, Messenger; C579096:DAPK1 protein, human; D064550:Death-Associated Protein Kinases
keywords: DAPk1; HSCC; PCR; lymph node metastasis; polymerase chain reaction; prognosis