Telomerase components as a diagnostic tool in human oral lesions

Abstract

Telomerase activity is considered to be a diagnostic marker of malignancy since most malignant cells express this activity and most somatic cells do not. However, the detection of telomerase activity is rather complicated and is affected by many factors. Recently, human telomerase components were cloned and found to consist of 3 subunits. We assessed which component of telomerase best correlates with malignancy in order to study the possibilities for developing a new diagnostic marker. Telomerase activity was measured by a telomeric repeat amplification protocol (TRAP) assay, and the telomerase components hTR, hTRT‐mRNA and TP1‐mRNA were detected by the reverse transcriptase‐polymerase chain reaction (RT‐PCR). Twenty‐five of 26 oral malignant lesions, 9 of 22 benign lesions and none of 19 normal control tissues exhibited distinct telomerase activity. hTR and TP1‐mRNA expression levels were detected in all malignant lesions and normal control tissues and had no significant correlation with the telomerase activity results. In contrast, hTRT‐mRNA expression was closely associated with telomerase activity. All lesions expressing hTRT were telomerase positive. In addition, some samples of dysplastic lesions, benign tumors, lichen planus and normal mucosa exhibiting poor telomerase activity revealed weak expression of hTRT. Expression levels of hTRT‐mRNA positively correlated with clinical and pathological findings. Detection of hTRT‐mRNA by RT‐PCR appeared to be more sensitive for telomerase than measurement of telomerase activity by the TRAP assay. Detection of hTRT‐mRNA may provide information useful in the diagnosis of oral malignancies. Int. J. Cancer 80:1–4, 1999. © 1999 Wiley‐Liss, Inc.

Increased telomerase activity and hTERT expression in human salivary gland carcinomas

“…2). These findings are in accordance with the results of previous studies of telomerase components in other malignant tumors (14,26,27).…”

“…mRNA expression of telomerase components in salivary gland tissues has been scarcely investigated (22,26). In the present study, hTERT mRNA was highly expressed in malignant tumors and correlated with the telomerase activity.…”

Telomerase activation cooperates with inactivation of p16 in early head and neck tumorigenesis

“…For these reasons, we analysed the telomerase activity of our samples using the TRAP method. Although the telomerase activity levels cannot be considered as quantitative due to the exponential nature of the PCR amplification, we and others (Sumida et al, 1999;Haik et al, 2000) have consistently shown that differences in telomerase activity levels can be shown reproducibly using the TRAP assay. Therefore we felt entitled to split telomerase-positive lesions in two groups of high and low level of expression depending on the increase of absorbance.…”

The immortalizing and transforming ability of two common human papillomavirus 16 E6 variants with different prevalences in cervical cancer

“…Telomerase activity correlates with levels of hTERT messenger RNA (Kyo et al, 1999;Sumida et al, 1999;Shamanin et al, 2008), which is the rate-limiting determinant of the enzymatic activity of telomerase (Kyo et al, 1999). Consequently, we measured hTERT messenger RNA levels using quantitative reverse transcriptase-PCR (Kirkpatrick et al, 2004 based on sensitive and specific Taqman chemistry previously optimized in our laboratory (DeCarlo et al, 2008).…”