抑癌基因PTEN与食管癌

PTEN是近年发现的一种与细胞信号传导途径有关的具有双特异性磷酸酶活性的新型抑癌基因。研究表明,该基因的突变与人类多种恶性肿瘤的发生发展密切相关。近年来国内外的学者在食管癌组织中发现,虽然该基因发生突变的频率较低,但其蛋白表达却普遍下降,表达程度与食管癌的恶性程度及预后密切相关。因此,PTEN的低表达可能参与了食管癌的发生发展过程。     

Infrequent genetic alterations of the PTEN gene in Japanese patients with sporadic prostate cancer

Prostate cancer is a major cause of cancer death among elderly men in America, Europe, and Japan. However, the molecular mechanism of carcinogenesis is not yet well characterized. Frequent loss of heterozygosity (LOH) on chromosome 10q was reported in prostate cancer, and a candidate tumor suppressor gene, PTEN, was isolated on chromosome band 10q23.3. To investigate the genetic alterations of PTEN, we examined 45 primary prostate cancer specimens. LOH at the PTEN locus was observed in two (11.1%) of 18 tumors. However, no mutations were observed in any of the primary prostate cancers. These data suggest that mutation of the PTEN gene does not play a major role in prostate carcinogenesis of Japanese patients. Received: February 6, 1998 / Accepted: July, 3, 1998     

肾细胞癌中抑癌基因PTEN的表达及生物学意义

目的 :研究抑癌基因PTEN在肾细胞癌的表达及其生物学意义。方法 :应用免疫组织化学S P法检测 5例正常肾组织、18例癌旁肾组织和 40例肾细胞癌组织中抑癌基因PTEN的表达。结果 :5例正常肾组织和 18例癌旁肾组织均有较强的PTEN蛋白的表达 ,二者PTEN蛋白的表达强度、阳性细胞的分布形式无差异。抑癌基因PTEN在肾细胞癌中的表达不同于正常肾组织和癌旁肾组织 ,12 5 %的肾细胞癌呈PTEN蛋白阴性 ;17 5 %的肾细胞癌PTEN蛋白呈弱阳性 ;70 %的肾细胞癌PTEN蛋白呈阳性或强阳性 ,与癌旁组织PTEN蛋白的染色强度无差异。PTEN蛋白阴性的肾细胞癌 ,肾门淋巴结转移率为80 % ;PTEN蛋白阳性的肾细胞癌 ,肾门淋巴结转移率为 2 0 %。PTEN蛋白阴性肾细胞癌的肾门淋巴结转移率与PTEN阳性肾细胞癌的肾门淋巴结转移率比较 ,差异有显著性 (P <0 0 5 )。结论 :肾细胞癌中存在着抑癌基因PTEN的表达缺失和异常 ;抑癌基因PTEN的表达异常可能与肾细胞癌的发生、发展有关 ,抑癌基因PTEN是肾细胞癌的一种新的相关基因。     

膀胱移行细胞癌中PTEN的表达分析

目的研究PTEN在膀胱移行细胞癌（TCC）中的表达。方法应用免疫组织化学染色方法观察52例TCC标本PTEN的表达情况。结果TCC组中PTEN的阳性表达率为71.2%,而10例正常膀胱粘膜组织PTEN表达均为阳性。PTEN表达与膀胱肿瘤病理分级、临床分期密切相关。结论PTEN的异常表达在TCC的发生、发展过程中起重要作用。该指标的检测有助于预后判断。     

Lack of PTEN expression in endometrial intraepithelial neoplasia is correlated with cancer progression

We tested the hypothesis that PTEN inactivation may stratify cancer progression risk among putative endometrial hyperplasias, classified prognostically by means of the morphometric D score (DS). The DS, calculated from 3 morphometric variables measured in routine hematoxylin-eosin-stained endometrial biopsy slides, is the most sensitive and specific method of endometrial cancer risk prediction currently available. Clinical outcomes of 103 women with endometrial hyperplasia on biopsy were tallied according to the DS. Seven (7/103; 7%) patients with carcinoma during follow-up were all distributed within the high-risk prognostic group (ie, DS <1 = endometrial intraepithelial neoplasia [EIN]) (7/21; 33% progression). None of the 82 cases with a DS higher than 1 progressed. All cases that progressed were PTEN null, indicating that this genotype is capable of further stratifying cancer progression risk in hyperplasias irrespective of histological categorization. However, only 16% of the PTEN-null cases progressed. When PTEN expression pattern was combined with EIN, the prognostic power was greatly increased (specificity from 63% for PTEN and 85% for EIN to 93% when combined; positive predictive value from 16% and 33% to 50%). We conclude that loss of PTEN expression is the first biomarker in EIN that increases the accuracy of the prognostic DS to predict cancer progression risk. Unless endometrial hyperplasias are stratified by histological morphometric D-Score, PTEN has a low positive predictive value.     

PTEN基因对人肝癌细胞系HHCC作用的研究

目的：研究PTEN基因对人肝癌细胞系HHCC细胞恶性表型及凋亡的影响。方法：将PTEN真核表达载体pBabe-PuroPTEN及空质粒pBabe-Puro，通过脂质体介导的基因转染方法，转入该基因表达缺失的HHCC细胞系中，嘌呤霉素筛选获得稳定表达PTEN基因的转染细胞。通过平板克隆形成试验、DNA凝胶电泳、相差显微镜和电镜，观察PTEN基因对人肝癌细胞系HHCC恶性表型及凋亡的影响。结果：转染后的细胞，经原位杂交、免疫组织化学检测证实，有PTEN mRNA及其蛋白的表达；平板克隆形成试验证实，转染PTEN基因后，细胞形成克隆的能力降低；转染PTEN的细胞在相差显微镜和电镜下可出现典型的凋亡形态学改变；DNA琼脂糖凝胶电泳呈现出明显的梯状条带。结论：外源性PTEN基因导入HHCC细胞后，可降低HHCC的细胞的恶性表型，并促进凋亡发生。     

子宫内膜癌中Rb2/P130、PTEN及Ki-67的表达及意义

目的 探讨正常子宫内膜、子宫内膜增殖症及内膜癌组织中Rb2/P130、PTEN及Ki-67的表达以及与子宫内膜癌发生的关系.方法 应用免疫组化SP法检测30例正常子宫内膜组织、32例单纯型增生过长、31例复杂型增生过长、36例不典型增生、64例子宫内膜癌组织中Rb2/P130、PTEN和Ki-67的表达.结果 Rb2/P130、PTEN蛋白在正常子宫内膜、单纯性增生过长、复杂型增生、不典犁增生、子官内膜癌组织中的阳性表达率依次递减,而Ki-67的阳性表达率依次递增,子宫内膜癌和不典型性增生中Rb2/P130、PTEN阳性表达率明显低于正常增生期子宫内膜和单纯性增生,差异均有显著性(P均<0.01),而Ki-67的阳性表达率明显高于正常增牛期子宫内膜和单纯性增生过长,差异均有显著性(P均<0.01).Rb2/P130、PTEN阳性表达缺失与组织学分级有关(P均<0.01)、与子宫肌层浸润程度无关,Rb2/P130阳性表达缺失与淋巴结转移无关,PTEN阳性表达缺失与淋巴结转移有关(P<0.05),而Ki-67阳性表达与组织学分级、临床分期及淋巴结转移有关(P<0.01,P<0.05,P<0.01),与子宫肌层浸润程度无关.Rb2/P130、PTEN蛋白表达与Ki-67呈负相关(P<0.003.P<0.000).结论 Rb2/P130、PTEN蛋白与Ki-67的异常表达与子宫内膜癌的发生相关,有可能成为子宫内膜组织早期癌变的有用标记物.     

星形细胞瘤中PTEN和CB表达与侵袭性的关系

目的 探讨ＰＴＥＮ和组织蛋白酶－Ｂ（ＣＢ）表达与星形细胞瘤恶笥程度和侵袭性的关系。方法 应用免疫组化方法检测５６例星形细胞瘤标本中ＰＴＥＮ和ＣＢ的表达,分析其与肿瘤恶笥程度和侵袭性的关系。结果 ＰＴＥＮ阳性染色主要定位于细胞质中,５６例星形细胞瘤中ＰＴＥＮ阳性表达３４例（６１％）,高分化组（Ⅰ和Ⅱ组）２３／２７例（８５％）和低分化组（Ⅲ和Ⅳ级）１１／２９例（３８％）之间差异显,明显高于低分化组（     

PTEN loss in intraductal carcinoma of the prostate has low incidence in Japanese patients

Clinical and genomic features of prostate cancer (PCa) vary considerably between Asian and Western populations. PTEN loss is the most frequent abnormality in intraductal carcinoma of the prostate (IDC-P) in Western populations. However, its prevalence and significance in Asian populations have not yet been well studied. In the present study, we evaluated PTEN expression in IDC-P in a Japanese population and its association with ERG expression. This study included 45 and 59 patients with PCa with and without IDC-P, respectively, who underwent radical prostatectomy. PTEN loss was observed in 10 patients with PCa with IDC-P (22%) and nine patients with PCa without IDC-P (17%). ERG expression was relatively frequent in patients with PCa with PTEN loss, although a significant difference was not observed. The co-occurrence of PTEN loss and ERG expression was observed in four patients with PCa with IDC-P and one without IDC-P. PTEN loss and ERG expression did not affect progression-free survival, regardless of the presence of IDC-P. The frequency of PTEN loss in IDC-P is lower in Asian patients than in Western patients. Our results indicate that mechanisms underlying IDC-P in Asian populations are different from those of Western populations.     

人PTEN基因表达载体的构建及其在U251细胞中的表达

背景与目的:克隆人野生型和突变型PTEN的cDNA并构建其表达载体,探讨该表达质粒在人星形胶质瘤细胞U251中的表达情况.材料与方法:分别从新鲜胎盘组织和结肠癌组织中提取总RNA,采用RT-PCR的方法扩增人野生型和突变型PTEN基因全长cDNA,分别克隆入pMD 18-T载体上,经PCR、酶切鉴定均为阳性的克隆,进行核苷酸序列分析.再分别将两段基因定向克隆入pcDNA3.1( )载体中构建表达载体,转染入U251细胞.结果:成功克隆了人野生型及突变型PTEN cDNA并成功构建其表达载体,发现突变型PTEN蛋白对细胞生长无明显抑制作用,而野生型PTEN蛋白对细胞生长有明显抑制作用.结论:PTEN可能能抑制肿瘤细胞生长,为后进一步开展PTEN对肿瘤相关功能的研究奠定基础.