Measurement of Telomerase Activity and Telomerase Reverse Transcriptase Expression in Gastric Fluid and Tissue for Early Diagnosis of Stomach Cancer / 대한소화기학회지

BACKGROUND/AIMS: Telomerase activity and telomerase reverse transcriptase (TERT) expression have been proposed as a marker for malignancy. However, little is known about those markers in intestinal metaplasia (IM). This study was performed to evaluate the usefulness of telomerase activity in gastric washing fluid and TERT expression in tissue as a marker for early diagnosis of stomach cancer. METHODS: Gastric washing fluid and biopsies were taken endoscopically. We examined the telomerase activity by telomeric repeat amplification protocol (TRAP) and the TERT expression by semiquantitative reverse transcription-polymerase chain reaction in 26, 21 and 15 cases of cancer, IM, and normal mucosa respectively. RESULTS: The telomerase activity was positive in 65% of cancer, 44% of incomplete IM, and 33% of complete IM. The TERT was expressed in 89% of cancer, 81% of IM, but not in normal mucosa. The TERT expression level was higher in cancer and incomplete IM than in complete IM and normal mucosa (p<0.05). CONCLUSIONS: Telomerase activity in gastric washing fluid and TERT expression in tissue may have limited usefulness as a marker for the early diagnosis of stomach cancer. However, the increased levels of TERT expression in IM and cancer suggest that TERT expression may be associated with carcinogenesis in stomach cancer.

Telomerase Activity in Various Benign, Premalignant and Malignant Skin Tumors / 대한피부과학회지

BACKGROUND: Telomerase is a ribonucleoprotein complex with RNA-dependent DNA polymerase which is necessary in maintenance of the length of chromosome, and therefore, in preventing genomic instability. Its activity is regarded as an indicator of cell immortalization. So far, there is no comprehensive answer on which step the telomerase activity is required; in some studies, telomerase activity has been found in benign, premalignant, and malignant conditions equally, which means it affects early stage of carcinogenesis, but in other studies, it has been found in malignant conditions at a higher rate. OBJECTIVE: This study was performed to examine telomerase activity in normal and skin cancer tissues and to assess the role of telomerase in the development of malignant transformation of skin cancer by examining benign, premalignant, and malignant conditions together. METHODS: Telomerase activities in four benign skin tumors, five precancerous lesions, and 17 skin cancer tissues of the skin were measured by a method telomeric repeat amplification protocol(TRAP). TRAP assay was also performed on normal control tissue of the same patients and eight skin tissues of the healthy volunteers. RESULTS: Telomerase activity was detected in 50% of benign tumors, 100% of precancerous, and 82% of malignant tissues. Among them, three out of four BCC tissues were shown to contain telomerase activity, whereas normal tissue of the same patients were not. No telomerase activity was detected in all of the eight skin samples of the healthy volunteers. CONCLUSION: Telomerase activities may be required at early stage of tumorigenesis as these activities are required for further steps down of the oncogenesis.