Telomerase activity in human brain tumours

Langford, Lauren A.; Piatyszek, Mieczyslaw A.; Shay, Jerry W.; Schold, S. Clifford

doi:10.1016/s0140-6736(95)91865-5

Cited by 201 publications

(128 citation statements)

References 9 publications

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“…Similarly, in Langford's study of 90 glial tumours, 75% of glioblastomas, but only 10% of anaplastic astrocytomas, were telomerase positive (Langford et al, 1995). These findings suggest that telomerase contributes to the malignant progression of glial tumours.…”

Section: Qualitative Telomerase Activitymentioning

confidence: 80%

“…Therefore, and as originally recommended (Kim et al, 1994;Piatyszek et al, 1995), the TRAP assay was performed with 27 PCR cycles. Although relative telomerase activity of some systemic cancers has been evaluated by dilution analysis (Hiyama E et al, 1995a and b;Hiyama K et al, 1995); Tahara et al, 1995) and has even been semiquantified by several investigators (Taylor et al, 1996), the telomerase activity of tumour tissues has mostly been assessed visually as being either positive or negative (Kim et al, 1994;Chadeneau et al, 1995;Langford et al, 1995;Piatyszek et al, 1995;Sommerfeld et al, 1996). To justify the visual, 'all-or-nothing' evaluation of telomerase activity, we quantified the TRAP assays of brain tumours and compared the results with visually determined positivity.…”

Section: Qualitative Telomerase Activitymentioning

confidence: 99%

“…For this reason, the internal standard is not suitable as a positive control. Therefore, we defined relative telomerase activity as the density of ladders divided by the density of the positive control -T98G, a fully immortalized human glioma cell line that expresses consistent telomerase activity (Langford et al, 1995). Relative telomerase activity for another established standard cell line, 293, is 92.2%.…”

Section: Qualitative Telomerase Activitymentioning

confidence: 99%

“…In one study, telomerase activity was detected in 90 of 101 human tumour samples (representing 12 tumour types) but in none of 50 samples of normal somatic tissue (representing four tissue types) (Kim et al, 1994). In a more recent study of 90 glial tumours, telomerase activity was detected in 75% of glioblastomas and in all oligodendrogliomas, but only 10% of anaplastic astrocytoma were telomerase positive (Langford et al, 1995). In all of those studies, however, telomerase activity was analysed qualitatively by assessment of the autoradiograms as either positive or negative.…”

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confidence: 99%

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Telomerase activity in 144 brain tumours

Sano

Asai²,

Mishima³

et al. 1998

Br J Cancer

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Summary Unlimited proliferation in immortalized cells is believed to be highly dependent on the activity of telomerase, a ribonucleoprotein that synthesizes telomeric repeats onto chromosome ends. Using a polymerase chain reaction-based telomeric repeat amplification protocol (TRAP) assay, we analysed telomerase activity in 99 benign and 45 malignant brain tumours. The TRAP assay results were quantitated by normalizing the telomerase activity of each specimen to that of human glioma cell line T98G to obtain the relative telomerase activity. Telomerase activity was also assessed visually from the autoradiograms as being positive or negative. One hundred and sixteen tumours with negative telomerase activity had null relative telomerase activity, whereas 28 tumours with positive telomerase activity had relative telomerase activities of 12-84.3% (mean 0% vs 36.1 ± 19.3%, P < 0.0001). Thus, quantification of telomerase activity confirmed the results of the visual evaluation of telomerase activity on autoradiograms. Based on the assessment, malignant brain tumours had a higher positive rate of telomerase activity than benign tumours (57.8% vs 2.0%, P < 0.001). These data indicate that positive telomerase activity is strongly associated with malignant brain tumours and is rather rare in benign tumours, such as neurinomas or meningiomas.

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Section: Qualitative Telomerase Activitymentioning

confidence: 80%

Section: Qualitative Telomerase Activitymentioning

confidence: 99%

Section: Qualitative Telomerase Activitymentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Telomerase activity in 144 brain tumours

Sano

Asai²,

Mishima³

et al. 1998

Br J Cancer

View full text Add to dashboard Cite

show abstract

“…Therefore, in order to improve the prognosis in this invariably fatal disease, it will be essential to explore novel forms of treatment. Recently it was shown that 70 ± 80% of tumors, including malignant gliomas, show very high levels of expression of telomerase, whereas, with a few exceptions, normal cells do not (Counter et al, 1992;Kim et al, 1994;Broccoli et al, 1995;Hiyama et al, 1995;Langford et al, 1995). Telomerase is the ribonucleoprotein enzyme complex that elongates telomeric DNA (TTAGGG) n (Blackburn, 1991) and is now thought to be an important step in the development of cellular immortality and oncogenesis (de Lange et al, 1994).…”

Section: Introductionmentioning

confidence: 99%