title: [Methylation and expression analysis of p16(INK4a) and RB genes in meningiomas].
abstract: OBJECTIVE
  To investigate the methylation of p16(INK4a) and RB gene, and the expression of p16(INK4a) in meningiomas.
  
  
  METHODS
  Methylation-specific polymerase chain reaction (MSP) was used to detect the methylation of p16(INK4a) and RB in 50 cases of meningiomas, and immunostaining was performed to analyze the protein expression of p16(INK4a) in 25 of those cases.
  
  
  RESULTS
  No methylation was found in the benign meningiomas, whereas methylation of p16(INK4a)or RB occurred in 6(37.5%) cases of grade II tumors and 4(28.6%) cases of grade III tumors, and among these cases, an atypical meningioma showed methylation of both genes. Thirteen cases showed p16(INK4a) positive expression, but none of them was methylated.
  
  
  CONCLUSIONS
  The methylation of p16(INK4a) or RB is related with the tumorigenesis and progression of atypical and anaplastic meningiomas, and a probable mechanism is that methylation causes the loss of expression and leads to dysfuncation of the p16(INK4a)/cyclin D1/CDK4/RB pathway.
authors.affiliation: Department of Infectious Disease, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041 PR China.
authors.forename: Mi-na
authors.initials: MN
authors.lastname: Chen
authors.forename: Qing
authors.initials: Q
authors.lastname: Mao
authors.forename: Yan-hui
authors.initials: YH
authors.lastname: Liu
authors.forename: Bo-yong
authors.initials: BY
authors.lastname: Mao
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019938:Cyclin D1 / Q000235:genetics; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases / Q000235:genetics; D019175:DNA Methylation; D005260:Female; D016161:Genes, Retinoblastoma; D019942:Genes, p16; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000235:genetics*; D008579:Meningioma / Q000235:genetics*; D008875:Middle Aged; D011518:Proto-Oncogene Proteins
chemical_list: D011518:Proto-Oncogene Proteins; D019938:Cyclin D1; C495900:CDK4 protein, human; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases