The Expression Of HTRT In PCa And Its Correlation With VEGF And MVD

Background: Telomerase is a specialized type of reverse transcriptase which is the enzyme required for the addition of telomeric repeats to the ends of chromosomes and thus maintains chromosomal stability leading to cellular immortalization and unlimited replication of neoplastic cells. Telomerase activity is present in most malignant tumors, but is inactive in most somatic cells. It suggested that telomerase may be a valid diagnostic marker of cancer. In the previous study, telomerase expression was always assayed by the telomeric repeat amplification protocol (TRAP). But, TRAP is too complicated and expensive to be used in clinical works. Expression of the gene encoding human telomerase reverse transcriptase (hTRT), the telomerase catalytic subunit gene, is associated with telomerase activity. hTRT is the rate-limiting determinant of telomerase reactivation. A significant correlation between hTRT expression and telomerase activity was observed. Thus, it is helpful in diagnosis that a new and convenient way to detect hTRT expression.Objective: To investigate the expression of hTRT in prostate cancer and its relationships with the expression of vascular endothelial growth factor (VEGF) and microvessel density (MVD) by means of immunohistochemistry (SP) combining with computer assisted. Materials and Methods: The expression of hTKT, VEGF and factor VIII-related antigen was assayed in 30 cases of prostate cancer and 30 cases of benign prostatic hyperplasia. Results:(1) hTRT expression was detected in 19 of 30 prostate cancer and 5 of 30 benign prostatic hyperplasia. The expression of hTRT was significantly higher in carcinoma tissue than in BPH (P<0.05). It increased with tumor grade developing, but no statistically significant relationship between histological grades of PCa and the level of hTRT was found (P>0.05).(2) VEGF expression was detected in 23 of 30 prostate cancer and 14 of 30 benign prostatic hyperplasia. The expression of hTRT was significantly higher in carcinoma tissue than in BPH (P<0.05). It increased with tumor grade developing, but no statistically significant relationship between histological grades of PCa and thelevel of VEGF was found (P>0.05).(3) MVD count was significantly higher in carcinoma tissue than in BPH (P<0.05), and MVD was correlated with tumor differentiation (P<0.05).(4) There was no significant difference between the sensitivity of hTRT and that of VEGF (P>0.05). But the specificity of hTRT was significantly higher than that of VEGF (P<0.05).(5) MVD count in positive group of hTRT or VEGF was higher than that in negative ones. A significant correlation was observed between hTRT and VEGF expressions.Conclusion:(1) The expression of hTRT is significantly related to prostate tumorigenesis. Detection of hTRT at the cellular level by immunohistochemistry is achievable and may have utility in cancer diagnosis. The expression of hTRT correlated with that of VEGF and MVD in prostate cancer, but the mechanisms is not clear yet.(2) The relationship between VEGF and MVD is not only correlated but also independent. The expression of VEGF is a malignantphenotype in prostate cancer and is positively related to the angiogenesis. But the level of VEGF did not correspond with histological grades of PCa. MVD is also an important quantitative parameter to indicate biological property of prostate cancer and it corresponds well with the grading of tumor.