Overexpression and increased activity of the small Rho GTPase Rac1 has been linked to squamous cell carcinoma of the epidermis and mucosa in humans. Targeted deletion of Rac1 or inhibition of Rac1 activity in epidermal keratinocytes reduced papilloma formation in a chemical skin carcinogenesis mouse model. However, a potential role of Rac1 in HPV- and UV-light induced skin carcinogenesis has no...

Recent studies have demonstrated a strong association between carcinogenesis and re-activation of telomerase in various human tumors. In the present study, we have analyzed the telomerase activity in 105 oral mucosal samples, including normal mucosa and premalignant and malignant lesions, by using the telomeric repeat amplification protocol assay. The telomerase activity was detected in normal ...

Telomerase activity is known to be absent from most normal and well-differentiated tissues, although being detectable in the vast majority of malignant tumors. An increasing number of reports demonstrate that telomerase may be activated in benign tumors, such as adenomas. We have investigated a series of normal and neoplastic thyroid tissues for the presence of telomerase activity. As expected,...

Telomerase is one of the major components of the telomeres -- linear eukaryotic chromosome ends - maintenance system. Linear chromosomes are shortened during each cell division due to the removal of the primer used for DNA replication. Special repeated telomere sequences at the very ends of linear chromosomes prevent the deletion of genome information caused by primer removal. Telomeres are sho...

Human telomerase is a ribonucleoprotein complex composed of at least the reverse catalytic transcriptase hTERT and RNA component hTR. The enzyme stabilizes telomere length and thereby contributes to unlimited cell proliferation, i.e. immortality. Reactivation of telomerase activity during carcinogenesis is a common hallmark in most human tumor types. Consequently, telomerase is an attractive mo...

The aim of this study was to reveal whether 3 biomarkers (p16INK4a, ProEx C, and human papilloma virus DNA) are useful in the diagnosis of cervical intraepithelial neoplasia and whether they could predict disease progression of cervical intraepithelial neoplasia-1. We analyzed 252 cervical specimens: nondysplastic mucosa (n = 9), cervical intraepithelial neoplasia (n = 229), and squamous cell c...

Background: Carcinomas of esophagus, mostly squamous cell carcinomas, occur throughout the world. There are a number of suspected genetic or environmental etiologies. Human papilloma virus (HPV) is said to be a major etiology in areas with high incidence of esophageal carcinoma, while it is hardly detectable in low incidence regions. This study was designed to evaluate the prevalence of HPV in ...

Somatic mutations activating telomerase reverse-trancriptase promoter were recently identified in several tumour types. Here we identify frequent similar mutations in human hepatocellular carcinomas (59%), cirrhotic preneoplastic macronodules (25%) and hepatocellular adenomas with malignant transformation in hepatocellular carcinomas (44%). In hepatocellular tumours, telomerase reverse-transcri...

The telomerase enzyme is a reverse transcriptase capable of replacing the telomeric DNA sequences that are lost at each cell division. Telomerase activation permits extended cell proliferation beyond normal senescence checkpoints, and accordingly, telomerase activity has been detected in a wide range of malignant cells and tissues but is absent in terminally differentiated somatic cells. To dat...