Telomerase Activity And Its Clinical Significance

Using a modified non-radioisotope telomeric repeat amplification protocol (TRAP) -silver staining assay, telomerase activity was examined in different human tissues or patients with hemopathy . In attempt to reveal the molecular mechanism of tumorigenesis, and investigate the relationship between telomerase activity and cancer, and determine the diagnostic value of telomerase activity in tumor early diagnosis, differential diagnosis and evaluation of therapeutic efficiency and prognosis, and analyze the possibility of the detection of telomerase activity as a useful tumor marker. Furthermore, this should facilitate a further understanding of telomerase biology, potentially leading to diagnostic and therapeutic applications.Telomerase activity were detected in 226 different tissues (including 147 malignant tumor , 44 benign tumor tissues and 35 normal tissues) ,51 hydrothorax samples , 96 hemopathy samples and immortal cells . We analyzed the relationship between telomerase activity and the clinicopathologic features , and the effect of chemotherapy on telomerase activity in breast cancer . The assay sensitivity is 83 % , specificity is 88.6 % , and the overall accuracy is 96.8 % . This result can satisfy the clinical requirement and the assay is more suitable for clinical application .The results showed : 1 ) Of 147 malignant tumor samples, 122 expressed telomerase activity , whereas 5 of 44 (11.37 %) nonmalignant samples and 4 of 35 adjacent normal tissues did . Positivity was observed in 86.84 % of lung cancer , 94.74 % of esophageal carcinoma , 88.88 % of kidney carcinoma ,72.13 % of mammary cancer , 87.50 % of rectal cancer and 100 % of thyroma ,melanoma and cervical carcinoma . The presence of telomerase activity was observed in 51 of 63 leukemia (80.95 %) , while only 15.15 % of nonmalignant hemopathy . 2) The presence of telomerase activity was observed in 65 of 78 female patients (83.33 %) , 82.61 % of male patients , and 95.83 % of malignant tumor associated with lymph nodesmetastasis . There was no significant correlation between telomerase activity and lymphatic metastasis . 3) The positive rate of telomerase activity in mammary cancer before and after chemotherapy were 94.1 % and 44.4 % respectively , showing the great difference (P <0.01) . 4 ) The positive rate of telomerase activity in malignant hydrothorax was significantly higher than that in nonmalignant hydrothorax (P<0.01). The results indicate : 1) The positive telomerase activity is highly correlated with malignant tumor , and the high telomerase expression indeed correlated with the carcinogenesis and aggressiveness of cancer .Telomerase activity might be one of the important diagnostic and prognostic factors in tumor patients . 2) No significant correlation was found between telomerase activity and the clinicopathologic features , including age , sex , tumor location and lymph nodes metastasis . Telomerase activity might be a marker for early diagnosis and prediction relapse . 3 ) The detectable rate of the exfoliative cytologic examinations of the pleural fluids is lower , the diagnosis of malignant pleural effusions and the differentiation between malignant and nonmalignant effusions are sometimes difficult, and the assay has a higher sensitivity and specificity and less discomfort, so the detection of telomerase activity may be a useful adjunct to cytopathologic methods in the diagnosis of malignant pleural effusions . 4) The detection of telomerase activity after chemotherapy could be used to value the chemotherapeutic effect and prognosis ,and telomerase activity could be used as a chemosensitivity assay , further it exploit the facility of treating cancer by inhibiting telomerase activity.