Activation of the hTERT expression in squamous cell cervical carcinoma is not associated with gene amplification

Abstract

The hTERT gene encodes the telomerase catalytic subunit that plays a key role in cancer cell immortalization. Earlier, hTERT amplification was detected in squamous cell cervical carcinomas (SCC), however possible relations between elevated hTERT mRNA level and gene amplification was not studied. Here, we compared the hTERT expression and copy number in the same tumors by quantitative real-time PCR. The hTERT DNA copy number was virtually unchanged in all 33 studied tumors, when compared to normal tissues. This result was confirmed using two reference genes β-actin and β-D-glucuronidase. Nevertheless, the activation of hTERT expression was found in 80% of cases (37/46, p<0.001). There was no correlation between the degree of mRNA increase and the tumor size and/ or presence of metastases. No hTERT gene expression was observed in 20% of cases (9/46), while the control GADPH expression was unchanged. The detected elevation of the hTERT mRNA level was found using primers specific to functionally active full-length isoform of mRNA. Similar results were obtained with SCC cell lines carrying human papilloma virus (HPV) genomes. We conclude that frequent activation of hTERT expression in SCC is not associated with gene amplification.