Human telomerase catalytic subunit gene re-expression is an early event in oral carcinogenesis.

AIMS: Detection of telomerase catalytic subunit (hTERT) mRNA has been used as a surrogate marker for estimation of telomerase activity. The exact role and timing of telomerase re-activation, a key enzyme implicated in cellular immortalization and transformation, in the multistep process of oral carcinogenesis is still unknown. The aim was to test the hypothesis that (i) quantitative rather than qualitative differences exist in the level of hTERT mRNA expression between normal oral mucosa, different grades of oral epithelial abnormalities and squamous cell carcinomas of the oral cavity, and that (ii) hTERT gene re-expression is an important, probably early event in oral carcinogenesis. METHODS AND RESULTS: The relative quantity of hTERT mRNA was analysed in 45 frozen oral epithelia representing different morphological stages of oral carcinogenesis classified according to the Ljubljana classification and in 37 oral squamous cell carcinomas, using a commercially available LightCycler Telo TAGGG hTERT Quantification kit. hTERT mRNA was not detected in normal or reactive hyperplastic oral epithelia, but was present in 43% of atypical hyperplasias (premalignant lesions), 60% of intraepithelial carcinomas and 68% of oral squamous cell carcinomas. Statistical analysis revealed two groups of oral epithelial changes, with significant differences in the levels of hTERT mRNA expression: 1, normal and reactive hyperplastic oral epithelium, and 2, atypical hyperplasia, intraepithelial carcinomas and squamous cell carcinomas. CONCLUSION: These data suggest that hTERT gene re-expression represents an early event in the multistep process of oral carcinogenesis, already detectable at the stage of precancerous oral epithelial changes. Nevertheless, other genetic aberrations appear to be necessary for progression of oral epithelial abnormalities towards invasive squamous cell carcinoma.

Second-generation Hybrid capture test and Amplicor monitor test generate highly correlated hepatitis B virus DNA levels.

The performance of the Digene Hybrid Capture II HBV DNA Test HC II and the Roche Cobas Amplicor Monitor Test (Cobas-HBV) was evaluated on 252 serum samples. One hundred and seventy-three samples were HBV DNA positive and 75 HBV DNA negative by both assays. Four samples were HBV DNA positive by Cobas-HBV only. Linear regression analysis showed that the HBV DNA concentrations obtained from both assays were significantly related (n=173, r=0.976, P<0.0001). The results of the study show that Hybrid capture II and Cobas-HBV could be used equally in the management for patients with chronic HBV infection.

Comparative evaluation of semiautomated COBAS AMPLICOR hepatitis B virus (HBV) monitor test and manual microwell plate-based AMPLICOR HBV MONITOR test.

Comparative evaluation of the semiautomated COBAS AMPLICOR hepatitis B virus (HBV) MONITOR Test (COBAS-HBV) and manual AMPLICOR HBV MONITOR Test (AMPLICOR-HBV) on 208 serum samples revealed no significant difference in the sensitivities of the two assays. Twenty samples tested HBV DNA negative and 183 samples tested HBV DNA positive by both assays. Three samples tested positive by COBAS-HBV only and two samples tested positive by AMPLICOR-HBV only. HBV DNA concentrations determined by the two assays were significantly related (n = 183, r = 0.97, P < 0.0001), which indicates that COBAS-HBV could replace AMPLICOR-HBV. The major inconvenience of COBAS-HBV is the required performance of appropriate predilutions of high-titer samples in order to extend the narrow dynamic range of the assay.

Quantitative measurement of telomerase catalytic subunit (hTERT) mRNA in laryngeal squamous cell carcinomas.

We tested 30 laryngeal squamous cell carcinomas (LSCCs) and 30 matched control laryngeal samples from the same patients for the presence of human telomerase catalytic subunit (hTERT) mRNA by using the Roche LightCycler Telo TAGGG hTERT Quantification kit. The hTERT index was calculated to express the relative quantity levels of hTERT mRNA. hTERT mRNA was detectable in 10 out of 30 (33%) laryngeal tissues covered by normal and/or reactively hyperplastic laryngeal epithelium and 23 out of 30 LSCCs (77%). The mean hTERT indices were 0.15 for control non-cancerous laryngeal samples, 0.57 for grade I, 2.35 for grade II and 3.72 for grade III LSCCs. LSCCs without detectable hTERT mRNA (23%) tended to have lower grades of disease. No correlation was found between the levels of hTERT mRNA and tumour size or locoregional lymph node status. We believe that hTERT mRNA in normal and/or reactively hyperplastic laryngeal epithelium originates from the stem cells and corresponds to the self-renewal capacity of the squamous epithelium. However, the greater quantity of h TERT mRNA in LSCCs is the result of telomerase reactivation in the process of laryngeal carcinogenesis.

Seroprevalence of HIV-1 subtypes A-E among HIV-1 infected individuals from Slovenia.

To investigate the prevalence of HIV-1 subtypes A-E in Slovenia, 82 HIV-1 infected individuals were tested for the presence of HIV-1 subtype specific antibodies using a research competitive peptide enzyme immuno assay supplied by Boehringer Mannheim. In 74 individuals unambiguous results were obtained. As in other European countries, the majority of Slovenian HIV-1 infected individuals (86.5%) were infected with subtype B. Infections with subtypes C, A, D and E were detected in 8.1%, 2.7%, 1.3% and 1.3% individuals, respectively.

Comparative evaluation of first- and second-generation digene hybrid capture assays for detection of human papillomaviruses associated with high or intermediate risk for cervical cancer.

In the present study we comparatively evaluated the first- and second-generation Digene Hybrid Capture assays for detection of human papillomaviruses (HPV) associated with high or intermediate risk for cervical cancer in cervical specimens. Concordant results were obtained with 468 of 483 (96.8%) specimens. All 15 specimens which gave repeatedly discordant results were positive by the second-generation test only, and 14 of them tested PCR positive. The enhanced sensitivity of the second-generation assay is mainly a result of the reformulation of hybridization reagents and, to a lesser extent, a result of the addition of new HPV probes.