htert Expression correlates with myc over-expression in human prostate cancer

Abstract

Expression of the telomerase catalytic sub-unit (htert) constitutes a key step in the development of human cancer. Although htert regulation is still unclear, several studies suggest that c-myc may activate its expression. Prostate cancer is one of the most common malignancies among men in Western countries. Since de-regulated expression of myc as well as telomerase activation may contribute to the pathogenicity of this cancer, we investigated this pathway in prostate tumorigenesis. For this purpose, myc- and htert-mRNA expression was quantified in 33 sporadic prostate tumors using a real-time quantitative PCR assay based on TaqMan methodology, myc over- expression was observed in 19 (58%) of 33 tumors, whereas telomerase status evaluated by htert expression was observed in 22 (67%). There was no correlation between myc over-expression or htert expression level and tumor stage or Gleason grade. A significant association (p = 0.0024) was found between myc over-expression and elevated htert expression, indicating that the up-regulation of telomerase activity often observed in prostate tumors might be conferred through transactivation of htert by myc. It is likely that the ability of c-myc protein to stimulate expression of htert and thereby enhance telomerase activity represents an important step in prostate tumorigenesis. (C) 2000 Wiley-Liss, Inc.