title: Differential telomerase expression and telomere length in primary intracranial tumors.
abstract: BACKGROUND
  Telomerase activity and telomere length have been shown to be involved in controlling cell proliferation and regulating cell senescence. The authors examined telomerase activity and telomere length in intracranial tumors to determine the clinicopathological behavior of primary intracranial tumors with respect to telomerase expression and alteration of telomere length.
  
  
  METHODS
  Telomerase activity was examined in 139 brain tumor samples. Telomere length was examined in 138 of the 139 samples. These tumors included 61 meningiomas, 27 schwannomas, 19 high-grade neuroepithelial tumors, and 32 low-grade neuroepithelial tumors. Telomerase activity was measured with a telomerase polymerase chain reaction, enzyme-linked immunosolvent assay kit. Telomere length was examined by Southern blot analysis for the terminal restriction fragment length.
  
  
  RESULTS
  Telomerase activity was detected in 39.2% (20/51) of the neuroepithelial tumors. Detection rates were 47.4% (9/19) for anaplastic astrocytomas and glioblastomas and 34.4% (11/32) for low-grade neuroepithelial tumors. However, detectable telomerase activity was found in 30.8% (4/13) of atypical or malignant meningiomas, but was not detected in any schwannomas. There was a highly significant difference in the telomerase detection rate in neuroepithelial or non-neuroepithelial tumors (p = 0.001). Telomere elongation was found in 11.7% (7/60) of all meningiomas, 46.1% (6/13) of atypical or malignant meningiomas, and 14.8% (4/27) of schwannomas. Elongation of telomere length was detected in 12.6% (11/87) of the cases and 23.5% (12/51) in neuroepithelial tumors. This difference was also significant (p < 0.05). Telomere length was reduced in the majority, (75%, 3/4) of malignant or atypical meningiomas with detectable telomerase activity, but only 45% (9/20) of the neuroepithelial tumors.
  
  
  CONCLUSIONS
  These results indicate that telomerase activation may be a critical step in the pathogenesis of intracranial tumors. Telomere length elongation also indicates a high potential for malignant behavior in these tumors.
authors.affiliation: Department of Neurosurgery, Chang Gung Memorial Hospital, 123, Tao-Pei Road, Niaosung, Kaohsiung, Taiwan, R.O.C. chenmd@ms8.hinet.net
authors.forename: H J
authors.initials: HJ
authors.lastname: Chen
authors.forename: C L
authors.initials: CL
authors.lastname: Cho
authors.forename: C L
authors.initials: CL
authors.lastname: Liang
authors.forename: L
authors.initials: L
authors.lastname: Chen
authors.forename: H W
authors.initials: HW
authors.lastname: Chang
authors.forename: K
authors.initials: K
authors.lastname: Lu
authors.forename: T C
authors.initials: TC
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000201:enzymology / Q000235:genetics* / Q000401:mortality; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019098:Telomerase / Q000378:metabolism*; D016615:Telomere
chemical_list: D019098:Telomerase