title: Deregulated expression of the Per1 and Per2 in human gliomas.
abstract: BACKGROUND
  Growing evidence shows that the deregulation of the circadian clock plays an important role in the development of malignant tumors, including gliomas. However, the molecular mechanisms of genes controlling circadian rhythm in glioma cells have not been explored.
  
  
  METHODS
  Using reverse transcription polymerase chain reaction and immunohistochemistry techniques, we examined the expression of two important clock genes, Per1 and Per2, in 33 gliomas.
  
  
  RESULTS
  In this study, out of 33 gliomas, 28 were Per1-positive, and 23 were Per2-positive. The expression levels of Per1 and Per2 in glioma cells were significantly different from the surrounding non-glioma cells (P<0.01). The difference in the expression rate of Per1 and Per2 in high-grade (grade III and IV) and low-grade (grade 1 and II) gliomas was insignificant (P>0.05). While there was no difference in the intensity of immunoactivity for Per2 between high-grade gliomas and low-grade gliomas (r=-0.330, P=0.061), the expression level of Per1 in high-grade gliomas was significantly lower than that in low-grade gliomas(r=-0.433, P=0.012).
  
  
  CONCLUSIONS
  In this study, we found that the expression of Per1 and Per2 in glioma cells was much lower than in the surrounding non-glioma cells. Therefore, we suggest that disturbances in Per1 and Per2 expression may result in the disruption of the control of normal circadian rhythm, thus benefiting the survival of glioma cells. Differential expression of circadian clock genes in glioma and non-glioma cells may provide a molecular basis for the chemotherapy of gliomas.
authors.affiliation: Department of Neurosurgery in the Affiliated Hospital of Ningxia Medical University, Yinchuan, China.
authors.forename: He-chun
authors.initials: HC
authors.lastname: Xia
authors.forename: Zhan-feng
authors.initials: ZF
authors.lastname: Niu
authors.forename: Hui
authors.initials: H
authors.lastname: Ma
authors.forename: Shuan-zhu
authors.initials: SZ
authors.lastname: Cao
authors.forename: Shao-cai
authors.initials: SC
authors.lastname: Hao
authors.forename: Zhong-tao
authors.initials: ZT
authors.lastname: Liu
authors.forename: Fan
authors.initials: F
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000235:genetics / Q000503:physiopathology*; D002648:Child; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology*; D005910:Glioma / Q000235:genetics / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D056950:Period Circadian Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: C539022:PER1 protein, human; C421902:PER2 protein, human; D056950:Period Circadian Proteins; D012333:RNA, Messenger