title: Hypermethylation of IFN-γ in oral cancer tissues.
abstract: OBJECTIVE
  The study aimed to evaluate the methylation pattern of the interferon-gamma (IFN-γ) gene in oral cancer tissues compared with normal and benign oral disease tissues.
  
  
  METHODS
  The oral tissues were gained from the patients of 85 cases of oral squamous cell carcinoma (OSCC), 47 cases of oral dysplastic lesions, and 53 normal biopsies. IFN -γ methylation in oral tissues was verified through methylation-specific polymerase chain reaction (PCR) and DNA sequencing analyses, and the expression levels of IFN-γ messenger RNA (mRNA) and protein were detected using real-time reverse transcription (RT)-PCR and enzyme-linked immunosorbent assays, respectively. IFN-γ was localized in macrophages from oral tissues and detected via immunostaining.
  
  
  RESULTS
  IFN-γ mRNA and protein expression levels were evidently decreased in oral cancer tissues, whereas the IFN-γ methylation rate was significantly higher in malignant tumors than in benign and normal tissues (normal, 22.6%; benign, 38.3%; and cancer, 55.3%; P < 0.05). Furthermore, the expression of IFN-γ mRNA was significantly downregulated in oral tumors with methylation compared with tumors without methylation, as determined by real-time RT-PCR (4.76-fold difference; P < 0.05). Likewise, mRNA expression was downregulated by 6.79-fold in oral epithelial dysplasia tissues with methylation compared with those without methylation (P < 0.01). Co-immunostaining to detect MAC2 and IFN-γ demonstrated that macrophages comprised the main source of IFN-γ in oral tissues. IFN-γ methylation demonstrated a significant association with the clinical stage, histopathology grade, and primary tumor.
  
  
  CONCLUSIONS
  Aberrant IFN-γ promoter methylation may be involved in the process of tumorigenesis of oral cancer.
  
  
  CONCLUSIONS
  IFN-γ hypermethylation during the process of oral carcinogenesis could be useful for the clinical diagnosis and treatment for OSCC.
authors.affiliation: Department of Oral Medicine, The Second Hospital of Hebei Medical University, Heping Western Road 215, Shijiazhuang, Hebei, 050000, People's Republic of China.
authors.forename: Songbo
authors.initials: S
authors.lastname: Tian
authors.affiliation: Department of Thoracic Surgery, Tianjin Union Medical Center, 190 Jieyuan Road, Hongqiao District, Tianjin, Tianjin, 300121, People's Republic of China. chunyangjiang@126.com.
authors.forename: Chunyang
authors.initials: C
authors.lastname: Jiang
authors.affiliation: Department of Nephrology, Hongqi Hospital, Mudanjiang Medical College, 5 Tongxiang Road, Aimin District, Mudanjiang, Heilongjiang, 157011, People's Republic of China.
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Neurosurgery, Tangshan People's Hospital, Tangshan, Hebei, 063001, People's Republic of China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Xu
authors.affiliation: Department of Physical Examination, The Second Hospital of Hebei Medical University, Heping Western Road 215, Shijiazhuang, Hebei, 050000, People's Republic of China.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Physical Examination, The Second Hospital of Hebei Medical University, Heping Western Road 215, Shijiazhuang, Hebei, 050000, People's Republic of China.
authors.forename: Huizhen
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Physical Examination, The Second Hospital of Hebei Medical University, Heping Western Road 215, Shijiazhuang, Hebei, 050000, People's Republic of China.
authors.forename: Yinghuai
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Physical Examination, The Second Hospital of Hebei Medical University, Heping Western Road 215, Shijiazhuang, Hebei, 050000, People's Republic of China. tianyx689@sina.com.
authors.forename: Yanping
authors.initials: Y
authors.lastname: Liu
authors.affiliation: School of Public Health, North China University of Science and Technology, Jianshe Road 57, Tangshan, Hebei, 063000, People's Republic of China. mamamadong@163.com.
authors.forename: Dong
authors.initials: D
authors.lastname: Ma
mesh_terms: D063646:Carcinogenesis; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000378:metabolism; D019175:DNA Methylation; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D012333:RNA, Messenger; D007371:Interferon-gamma
keywords: Cytokines; IFN-γ; Methylation; Oral cancer; Tumorigenesis