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

Expression of the telomerase catalytic sub-unit (htert) constitutes a key s tep in the development of human cancer. Although htert regulation is still unclear, several studies suggest that c-myc may activate its expression. Pr ostate cancer is one of the most common malignancies among men in Western c ountries. Since de-regulated expression of myc as well as telomerase activa tion may contribute to the pathogenicity of this cancer, we investigated th is 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 wa s observed in 19 (58%) of 33 tumors, whereas telomerase status evaluated by htert expression was observed in 22 (67%), There was no correlation betwee n myc over-expression or htert expression level and tumor stage or Gleason grade. A significant association (p = 0.0024) was found between myc over-ex pression and elevated htert expression, indicating that the up-regulation o f 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 telomeras e activity represents an important step in prostate tumorigenesis. (C) 2000 Wiley-Liss, Inc.