Detection of telomerase activity and hTERT mRNA expression and its application for the diagnosis of gynecologic tumors

端粒酶是一种催化端粒DNA合成和延伸的细胞逆转录酶，在大多数恶性肿瘤中特异性激活，但在正常体细胞中通常无活性，因此端粒随着细胞分裂而逐渐缩短。维持端粒稳定性的机制是细胞克服复制性衰老所必需的，因此端粒酶激活可能是细胞永生和肿瘤发生的限速或关键步骤。人端粒酶逆转录酶（humantelomerasereversetranscriptase，hTERT）是端粒酶催化亚基蛋白，是决定端粒酶活性的关键酶，本研究探讨了检测端粒酶活性和hTERTmRNA表达在妇科肿瘤诊断和筛选中的应用价值。我们发现，大多数妇科肿瘤表达端粒酶活性，而相应的正常组织不。收集宫颈及子宫内膜脱落细胞，采用TRAP法和RT-PCR法检测端粒酶活性和hTERTmRNA表达。大约90%的宫颈癌或子宫内膜癌患者端粒酶活性或hTERTmRNA表达阳性，而没有任何病变的患者不到10%。50 ~ 60%的癌前病变（如上皮内病变（SIL））患者端粒酶活性或hTERTmRNA表达阳性，提示检测端粒酶活性或hTERTmRNA表达可作为肿瘤诊断和筛查的一种有用手段。

Telomerase is a cellular reverse transcriptase which catalyzes the synthesis and extension of telomeric DNA.This enzyme is specifically activated in most malignant tumors, but is usually inactive in normal somatic cells, and within which telomeres therefore progressively shorten with cell division. A mechanism to maintain telomere stability is required for the cells to overcome replicative senescence, and telomerase activation may therefore be a rate-limiting or critical step in cellular immortality and oncogenesis. Human telomerase reverse transcriptase (hTERT) is a catalytic subunit protein of telomerase and is a critical determinant of its enzymatic activity.In the present study, we examined the utility of detecting telomerase activity and hTERT mRNA expression for the diagnosis and screening of gynecologyc tumors. We found that most gynecologic cancers express telomerase activity while the corresponding normal tissues do not. Cervical and endometrial exfoliated cells were collected from the patients with or without cervical or endometrial lesions and telomerase activity and hTERT mRNA expression were detected by the TRAP assays or RT-PCR assays. Approximately 90% of the patients with cervical or endometrial cancer were positive for telomerase activity or hTERT mRNA expression, while less than 10% of those without any lesions were so. 50 to 60% of the patients with premalignant lesions, such as suqamous intraepithelial lesions (SIL) expressed telomerase activity or hTERT mRNA.These findings suggest that detection of telomerase activity or hTERT mRNA expression may be an useful tool for cancer diagnosis and screening.