Telomeric lengths and telomerase activity in liposarcomas

To assess the role of telomerase in the development of liposarcomas, we measured telomerase activity in 36 malignant and seven benign lipomatous neoplasias from 34 patients. A sensitive polymerase chain reaction-based telomerase assay (the telomeric repeat amplification protocol) was applied. Shortening or elongation of telomeric repeat fragment lengths, as measured by using hybridization with a telomere-specific oligonucleotide probe, was correlated with the presence of telomerase activity. The latter was demonstrable in 69% of malignant tumors. Benign tumors can be distinguished from malignant neoplasias on the basis of telomerase activity. However, telomerase expression seems to be characteristic of poorly differentiated liposarcomas. Myxoid/round cell liposarcomas exhibited a higher telomerase activity level than the classical low-grade variants. Telomerase activity was not correlated with age at the time of diagnosis or with sex. In most cases, telomerase-positive tumors showed higher proliferation indices than did neoplasias lacking telomerase. All eight recurrences expressed telomerase activity, reflecting a close association of telomerase with the biological behavior of liposarcomas. Our findings suggest that telomerase may play a key role in the establishment and progression of malignant lipomatous tumors.     

p27(kip1) protein expression correlates with survival in myxoid and round-cell liposarcoma.

PURPOSE: The p27(kip1) protein (p27) is a cyclin-dependent kinase inhibitor that has been shown to be an independent prognostic factor in a variety of human neoplasms. Low expression of p27 tends to occur in more aggressive neoplasms. The role of p27 as an independent prognostic factor in the spectrum of myxoid and round-cell liposarcomas has not been examined. MATERIALS AND METHODS: Forty-seven cases of myxoid and round-cell liposarcomas were examined. Clinicopathologic features and immunohistochemical expression of p27 and Ki-67 antigen were studied in all cases. Survival analysis was performed using the log-rank test and the Cox multivariate regression model. RESULTS: The male:female ratio was 1. 4:1, and the mean age at diagnosis was 45 years. The tumors were located in the lower extremities (94%) and retroperitoneum (6%). The median tumor size was 13.5 cm. The median follow-up was 6.3 years, and the overall 5- and 10-year survival rates were 76% and 67%, respectively. Low expression of p27 was identified in 34 cases (72%) and correlated with decreased metastasis-free (P =.026) and overall survival (P =.008). In a multivariate analysis, only round-cell differentiation and low expression of p27 independently predicted decreased metastasis-free and overall survival. CONCLUSION: p27 expression predicts the clinical behavior of myxoid and round-cell liposarcomas, even in neoplasms with few or no round-cell differentiation.     

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.     

肝细胞癌端粒酶活性及hTERT mRNA表达与术后早期复发的关系

目的：研究肝细胞癌端粒酶活性及人端粒酶逆转录酶（hTERT）mRNA表达与肝细胞癌术后早期复发的关系。方法：采用ELISA—TRAP法检测60例肝癌组织及其癌旁组织端粒酶活性，RT—PCR法检测hTERT mRNA表达，5例正常肝脏组织作为对照。分析端粒酶活性及hTERT mRNA表达与临床病理之间的关系。结果：肝癌组织端粒酶活性及hTERT mRNA表达阳性率分别为86．7％（52／60）及90％（54／60），癌旁组织端粒酶活性及hTERT mRNA表达阳性率分别为40％（24／60）及43．3％（26／60）。正常肝脏组织均未检测到端粒酶活性及hTERT mRNA表达。癌旁组织端粒酶活性及hTERT mRNA表达与术后早期复发及包膜浸润、门静脉侵犯、肝内转移等恶性肿瘤的恶性生物学行为有关。结论：癌旁组织端粒酶活性及hTERT mRNA表达可能是肝细胞癌术后早期复发的预后指标。     

端粒酶、细胞周期素D1在大肠癌中的表达及意义

目的　探讨端粒酶、细胞周期素D1(CD1)与大肠癌的发生、进展及预后的关系。方法　收集 2 4例手术切除的大肠癌标本 ,同时取距癌灶 5cm以外的癌旁组织及 10cm以外的正常组织。检测癌组织、癌旁组织及正常组织中CD1mRNA及端粒酶的表达。结果　 1.2 4例大肠癌组织端粒酶阳性率 87.5 % ;癌旁组织阳性率 4 .2 %。癌旁组织和正常组织均与癌组织有显著性差异 (P <0 .0 1)。端粒酶活性在癌灶直径 >3cm的病例中明显高于癌灶直径≤ 3cm者 (P <0 .0 5 ) ;浸润深度达浆膜层者明显高于浸润至肌层者 (P <0 .0 5 ) ;有淋巴结转移者明显高于无淋巴结转移者 (P <0 .0 5 ) ;Dukes分期高 (C、D期 )的明显高于分期较低 (A、B期 )者。 2 .CD1mRNA的表达在大肠癌、癌旁及正常组织中有明显差异。CD1mRNA的表达在浸润至浆膜层组明显高于浸润至肌层组 (P <0 .0 5 ) ;有淋巴结转移组及晚期病变 (DukesB C D期 )组亦明显高于无淋巴结转移及早期病变 (DukesA期 )组 (P <0 .0 5 )。 3.端粒酶阳性病例的CD1mRNA表达明显高于阴性病例。端粒酶活性与CD1表达呈正相关。结论　 1.端粒酶活化在大肠癌发生过程中起重要作用 ,并与大肠癌的进展、侵袭及转移有关。 2 .CD1过度表达与大肠癌的发生、发展及转移有关。 3.CD1过度表达可致细胞周期     

Amplification of hTERT and hTERC genes in leukemic cells with high expression and activity of telomerase

Reactivation of telomerase plays an important role in carcinogenesis. Malignant cells almost always possess high activity and expression of telomerase. The aim of this study was to see whether there is any relationship between telomerase activity and expression and hTERT and hTERC gene amplification in acute lymphoblastic leukemia (ALL) and non-lymphoblastic leukemia (ANLL) cells. In addition telomere length was tested in leukemic cells at the time of diagnosis and during remission. Expression of the three components of telomerase (hTERT, hTERC and TP1) as well as telomerase activity was found both in ALL and ANLL cells. Telomerase activity was diminished in patients in remission. The leukemic cells showed considerable heterogeneity of terminal restriction fragments, that is telomere length. ALL cells showed a variable pattern of telomere length in contrast to ANLL cells which produced a predominantly short telomere pattern. Telomere length in the lymphocytes of leukemia patients was shorter in remission as compared to the time of diagnosis. FISH analysis revealed amplification of hTERT and hTERC genes in ALL and ANLL cells. Quantitative analysis showed that leukemic cells possess higher number of hTERT and hTERC copies than the normal PBL. Our results suggest that the activation of telomerase in leukemic cells is connected with amplification of hTERT and hTERC genes. The high expression and activity of telomerase found in leukemic cells may be partially explained by amplified hTERT and hTERC genes. Amplification of the telomerase genes seems to be a common event in carcinogenesis and may play a role in telomerase reactivation leading to cell immortalization.     

Increased telomerase activity and elevated hTERT mRNA expression during multistage carcinogenesis of squamous cell carcinoma of the lung

BACKGROUND: Telomerase activation is believed to play a critical role in the immortalization of cells and carcinogenesis. Telomerase activity is undetectable in normal somatic cells (except for those cells undergoing proliferation) but is expressed in the majority of human tumors including lung carcinoma. The expression of hTERT mRNA has been found to be correlated with telomerase activity. In the current study, the authors analyzed telomerase activity and hTERT mRNA expression in preinvasive bronchial lesions using biopsy specimens obtained by fluorescence bronchoscopy. METHODS: The authors studied 150 bronchial biopsy specimens obtained by fluorescence bronchoscopy. The intensity of telomerase activity was determined by the fluorescence-based telomeric repeat amplification protocol method in 74 bronchial biopsy specimens (22 normal bronchial epithelium or bronchitis cases, 15 squamous metaplasia cases, 23 dysplasia cases, and 14 squamous cell carcinoma cases), and the level of hTERT mRNA was analyzed in another 76 specimens (24 normal bronchial epithelium or bronchitis cases, 15 squamous metaplasia cases, 20 dysplasia cases, and 17 squamous cell carcinoma cases) by real-time polymerase chain reaction. RESULTS: The mean values (+/- the standard deviation [SD]) of telomerase activity in normal bronchial epithelium or bronchitis, squamous metaplasia, dysplasia, and squamous cell carcinoma cases were 6.2 +/- 7.5, 13.9 +/- 14.8, 18.5 +/- 20.8, and 54.5 +/- 22.3 U/microg protein, respectively. The upper limit of telomerase activity in normal bronchial epithelium or bronchitis was 21 U/microg protein (mean + 2SD). It is interesting to note that, 5 of 15 squamous metaplasia biopsies (33%), 8 of 23 dysplasia biopsies (35%), and all squamous cell carcinoma biopsies (100%) exhibited levels of telomerase activity that were > 21 U/microg protein. The mean levels of hTERT mRNA in normal bronchial epithelium or bronchitis, squamous metaplasia, dysplasia, and squamous cell carcinoma cases were 891 +/- 840, 1936 +/- 1704, 3019 +/- 2607, and 12965 +/- 18008 copies/microg total RNA, respectively. Telomerase activity and hTERT mRNA expression were found to increase in proportion to the severity of histologic change from normal bronchial epithelium or bronchitis to squamous cell carcinoma. CONCLUSIONS: These results suggest that an increase in telomerase activity and hTERT mRNA expression are features of the early stages of the development of squamous cell carcinoma of the lung, with strong telomerase activity and hTERT mRNA expression being prominent during the latter stages.     

食管鳞癌组织端粒酶亚基的表达及端粒酶活性的关系

目的　探讨食管鳞癌组织中端粒酶活性、端粒酶逆转录酶 (h TERT)及端粒酶相关蛋白 - 1(TP- 1)的表达及其关系。方法　应用 TRAP-银染法对 45例食管鳞癌组织端粒酶活性的检测 ,同时应用原位杂交对癌组织切片进行 h TERT、TP- 1的 m RNA表达的检测。结果　癌组织端粒酶活性阳性率为 82 .2 %。癌组织中不同分化程度的端粒酶活性差异无显著性 (P>0 .0 5 )。有淋巴结转移者癌组织端粒酶活性明显高于无淋巴结转移者 ,差异有显著性(P<0 .0 5 )。癌组织中 h TERTm RNA表达的阳性率为 6 4.4%,TP- 1的阳性率为 6 2 .2 %。 h TERT的 m RNA表达与端粒酶活性密切相关 ,而 TP- 1的 m RNA表达与端粒酶活性无相关。结论　食管鳞癌组织中端粒酶活性及h TERT、TP- 1的 m RNA表达均较高。端粒酶活性与淋巴结转移有关。 h TERT与端粒酶活性有密切关系。     

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.     

Gastric cancer with high telomerase activity shows rapid development and invasiveness

Telomerase activity was reported to be activated in most immortal cells and cancers. As the clinical significance of telomerase activity in human gastric cancer is controversial, we investigated this activity using a telomeric repeat amplification protocol. The telomerase activity was tentatively defined by strength of activity as follows: 3+, observed with 0.06 microg of protein; 2+, observed with 0.6 microg of protein; 1+, observed with 6 microg of protein; 0, not observed under these three conditions. Telomerase activity was detected in 35 of 39 (89.7%) gastric cancer specimens. Tumors with high telomerase activities (2+/3+) tended to have a deeper invasion, lymphatic and vascular invasion, lymph node metastasis, liver metastasis, and peritoneal dissemination, as compared to findings in case of low telomerase activities (-/1+). Thus, telomerase activity of gastric cancer tissue may reflect the malignant potential of the tumor and intensive postoperative care might be required for such patients.