Markers telomerase

The demonstrated ZnO NR-enabled fluorescence sensitivity is even more remarkable, when considering the fact that such fluorescence enhancement of ZnO NR platforms is achieved without the use of chemical and biological ampliflcation processes, major improvements of detection apparatus and analysis software, or application of specially designed fluorophores. Although telomerase and cytokine assays are discussed in this section as example cases, the versatility and general applicability of ZnO NR-based assays can be extended to other disease-marker or biomarker systems. 

Diagnostic importance is also attributed to des-y-car-boxy prothrombin (60-80% positivity in HCC) (H.A. Liebman et af, 1984). (90, 120, 133, 154) It is synthesized in the normal hepatocytes and therefore also in HCC. The diagnostic accuracy in small hepatocellular carcinomas (< 3 cm) could be greatly improved by determining this precursor prothrombin (PIVKAII) in combination with AFP. A decrease in the factor-II index, i.e. (factor VII + factor X) - (factor II) = >15, has proved to be a specific and independent marker of HCC. In addition, isoferritins, Regan-AP, telomerase activity (99) and L-fucosidase as well as CEA variants may be helpful in the demarcation of HCC. Laboratory diagnosis of HCC is indeed much more reliable if various important parameters are added, (s. tab. 37.6)... 

Telomerase is normally active during embryogenesis, but is repressed in most somatic cells before or shortly after birth. Germline cells, activated lymphocytes, and other immortal cells show no shortening of telomere length and possess telomerase activity. Thus tumor cells should also show telomerase activity that can act as a specific marker of transformation. 

Hiyama E, Hiyama K. Telomerase as tumor marker. Cancer Lett 2003 94 221-33. 

Chen XQ, Bonnefoi H, Pelte MF, Lyautey J, Lederrey C, Movarekhl S, et al. Telomerase RNA as a detection marker in the serum of breast cancer patients. Clin Cancer Res 2000 6 3823-6. 

Eiedler W, Hoppe C, Schimmel B, et al. Molecular characterization of head and neck tumors by analysis of telomerase activity and a panel of microsatellite markers. Int J Mol Med. 2002 9(4) 417-423. 

Telomerase, described as a ribonucleoprotein enzyme that extends the sequences at the chromosomal ends (telomeres), is another strong candidate for a marker. It is active in over 90% of primary human tumors, but for the most part is inactive in normal cells. (As noted earlier, however, in hmited or inactive amounts it produces no changes, but in excess it leads to cancer, that is, unregulated cell growth.)... 

As for the effectiveness of microsatelhte markers, in a set of tests on nrine samples, over 90% of bladder tnmors were fonnd. And as telomerase is expressed selectively in almost all primary cancers, it is viewed as a promising molecnlar marker for detecting cancer. 

Telomerase has been associated with almost 90% of all malignant human cancers, making it the most prominent molecular marker known to date. Because of its association with malignancy, telomerase is also regarded as a novel diagnostic marker and a specific target for gene therapy or chemotherapy. 

Eor BRACO-19, an important decrease in the nuclear hTERT, together with the formation of cytoplasmic hTERT bound to ubiquitin may explain the telomerase activity down-regulation. Other antitumor agents have been also found to down-regulate telomerase activity and hTERT expression has been reported as a marker of cell proliferation. Thus, the simplest explanation for the effect of the G-quadruplex ligands to down-regulate telomerase activity is related to their antiproliferative activity. 

Dictyodendrin alkaloids have been described as the first telomerase inhibitors of marine origin and hence represent potential lead compounds in the quest for small molecule inhibitors of the tumor-marker enzyme. In a 2009 study, Fiirstner et al. [58] reported the synthesis of several members of the series, making use of FI—HMBC data. 

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