上皮性卵巢癌hTERT表达及端粒酶活性的研究

目的探讨人端粒酶反转录酶(hTERT)表达及端粒酶活性与卵巢癌发生、发展的关系,评价其可否作为卵巢癌的肿瘤标志物及预后指标.方法应用RT-PCR及端粒重复扩增方法对43例上皮性卵巢癌、11例良性卵巢肿瘤和卵巢正常组织以及4例交界性卵巢肿瘤共69份标本进行hTERTmRNA及端粒酶活性检测.结果hTERT表达及端粒酶活性率在卵巢癌中分别为83.7%(36/43)及76.7%(33/43),良性肿瘤中均为9%(1/11),在正常卵巢组织和交界性卵巢肿瘤中阴性,其差异在卵巢癌与良性肿瘤及正常组织间均有显著性(P值分别为0.0004及0.0001).hTERT及端粒酶阳性率在某些预后因素如肿瘤类型、组织学分级、临床分期及肿瘤转移之间的差异皆无显著性.结论卵巢癌中存在高频率的hTERT表达及端粒酶激活,表明hTERT作为端粒酶的催化亚基,在肿瘤细胞端粒酶的激活中起关键作用.hTERT表达及端粒酶活性可望作为有价值的肿瘤标志物而用于卵巢癌的早期诊断,但其预后价值尚有待于进一步研究.     

Differential telomerase activity, expression of the telomerase catalytic sub-unit and telomerase-RNA in ovarian tumors.

Telomerase activity has been found in a variety of malignant tumors but only rarely in benign tumors or normal tissues. In this study, we investigated telomerase activation in 37 ovarian tumors, including benign, borderline and malignant neoplasms. Telomerase activity was detected using the telomeric repeat amplification protocol (TRAP) in 13/16 ovarian carcinomas, 9/10 borderline tumors and 3/11 cystadenomas/fibromas. mRNA expression of the putative human telomerase catalytic sub-unit gene (hTERT) was detected by RT-PCR in 14/15 ovarian carcinomas, 8/10 borderline tumors and 4/11 cystadenomas/fibromas. In situ hybridization was performed to evaluate telomerase-RNA (hTR) expression in the corresponding paraffin-embedded tumors. Variable expression levels of hTR were found over neoplastic tumor cells. The highest levels of hTR expression were found predominantly in ovarian carcinomas. Although the amount of telomerase activity varied, significantly high levels of telomerase activity were found predominantly in ovarian carcinomas. hTERT mRNA expression was closely associated with telomerase activity. These findings suggest that up-regulation of hTERT and hTR is important for telomerase activation during malignant-tumor progression. Telomerase activation might therefore be a valuable diagnostic parameter that could help to identify potentially progressive lesions. However, the diagnostic and therapeutic implications of telomerase activation need to be clarified in clinical trials. Int. J. Cancer (Pred. Oncol.) 84:426-431, 1999.     

Telomerase in relation to clinicopathologic prognostic factors and survival in cervical cancer

We investigated, in cervical cancer, the relation between telomerase activity, telomerase RNA (hTR) and mRNA of the catalytic subunit of telomerase, hTERT, with "classic" clinicopathological factors as well as survival. Frozen specimens were obtained from 107 consecutive patients with cervical cancer, treated with surgery or radiotherapy with or without chemotherapy. Telomerase activity was determined with fluorescence-based TRAP and hTR and hTERT with semi-quantitative RT-PCR. Eight normal cervical specimens served as controls. Analysis of prognostic factors and survival was limited to early-stage patients, treated primarily with radical hysterectomy. Telomerase activity was not detected in normal cervices and was present in 85 of 107 (79%) cervical cancers (p < 0.001). hTR was detected in all normal cervices and cervical cancers, while hTERT mRNA was detected in 1 of 8 (13%) normal cervices and in 83 of 104 (80%) cervical cancers (p < 0.001). In contrast to semi-quantitative hTR expression levels, semi-quantitative hTERT mRNA levels were related to telomerase activity levels (p < 0.01). In all patients, telomerase activity levels were related to differentiation grade (p < 0.05) but not to stage and histotype. In early-stage patients, telomerase activity, hTR and hTERT were not related to tumor volume, vascular invasion or presence of metastatic lymph nodes. Tumor volume, vascular invasion and presence of metastatic lymph nodes were related to (progression-free) survival, while telomerase activity and its subunits were not. Frequent up-regulation of telomerase activity and hTERT mRNA is especially observed in cervical cancers, while hTR is also detected in normal cervices. Telomerase is not applicable as a prognostic factor in early-stage cervical cancer patients.     

Expression of telomerase genes in thyroid carcinoma

Telomerase (T) is a ribonucleoprotein complex that includes the telomerase RNA component (hTR), telomerase associated protein (TP1) and the telomerase catalytic subunit (hTERT). Telomerase has been shown in stem cells and found to be activated in tumor tissues and immortalized cells. We wanted to test whether the expression of the telomerase complex subunits correlate with the enzyme activity in human thyroid tissue. Hence, we determined the expression of hTERT, hTR and TP1 mRNA by RT-PCR and compared the results to telomerase activity as detected by the telomeric repeat amplification protocol (TRAP) assay. Fifteen benign goiters (G), 11 follicular carcinomas (FTC) including 2 oncocytic follicular carcinomas (also called Hurthle cell carcinoma, oFTC), 12 papillary carcinomas (PTC) including 3 microcarcinomas (mPTC), and 12 undifferentiated anaplastic thyroid carcinomas (UTC) were investigated. Experienced pathologists performed histological and pTNM classification in each specimen. RT-PCR analysis revealed that TP1 was ubiquitously expressed in all G and carcinomas. hTR was expressed in 4 out of 15 G, in 2 out of 3 mPTC, in 5 out of 9 PTC, in 5 out of 9 FTC, in all oFTC and in 9 out of 12 UTC samples. Regarding all carcinomas, no statistically significant correlation was observed between hTR-expression and tumor stage, lymph node or distant metastasis. hTERT-expression was associated with malignancy and tumor stage. All mPTC and 13 out of 15 G did not express hTERT, whereas all samples of pT3-4 tumor stage of FTC, PTC, UTC and all oFTC were positive for hTERT. No telomerase activity could be detected in G. Telomerase activity in carcinoma was only measurable in tissues that expressed the catalytic subunit hTERT. Our data indicate that telomerase activity is up-regulated in neoplastic cells. In contrast to TP1 and hTR, hTERT and telomerase activity may be of help in identifying invasive tumors and may be additional markers for classification of benign goiter and malignant thyroid carcinoma.     

肺癌组织中端粒酶基因与端粒酶活性关系的研究

目的 探讨肺癌组织中端粒酶基因hTR、hTERT与端粒酶活性的表达是否与肺癌的发生发展有关，深入了解端粒酶基因对端粒酶活性的调控是在基因水平还是在转录水平。方法 采用TRAP－PCR和RT－PCR方法分别检测68例肺癌组织及相应癌旁肺组织中端粒酶活性、端粒酶基因hTR和hTERP的表达。结果 68例肺癌组织中端粒酶阳性率为79．4％（54／68）,hTR阳性率为98．5％（67／68）,hTERT阳性率为91．2％（62／68）。68例癌旁组织中无一例表达端粒酶阳性，但大多数癌旁组织均表达hTR(62/68,91.2%)，仅7例hTERT表达阳性（10．3％），与hTR相比，hTERT同端粒酶具有更高的一致性，其一致率为89．0％（121／136），而ThTR与端粒酶的一致率为43．4％（59／136）。结论 端粒酶的活性可能在肺癌发生发展中起重要的作用。hTR与hTERT可能是在转录后或翻译后水平对端粒酶进行调控的。