成人急性白血病p16基因的纯合缺失及甲基化研究

目的　观察成人急性白血病p16基因的纯合缺失及甲基化的情况。方法　用PCR法对成人急性白血病患者骨髓标本进行p16基因第 1、第 2外显子纯合缺失及甲基化检测。结果　 1) 71例成人急性白血病患者中p16基因纯合缺失 2例 ,均为B ALL ,AML及正常对照组p16基因未见纯合缺失 ;2 ) 2 8例ALL中 ,5例发生异常甲基化 ;43例ANLL中 ,有 7例发生了异常甲基化。结论　p16基因缺失、异常甲基化可能与白血病的发生及预后有关     

成人急性白血病p16基因的纯合缺失及甲基化研究

目的观察成人急性白血病p16基因的纯合缺失及甲基化的情况。方法用PCR法对成人急性白血病患者骨髓标本进行p16基因第1、第2外显子纯合缺失及甲基化检测。结果1)71例成人急性白血病患者中p16基因纯合缺失2例，均为B-ALL，AML及正常对照组p16基因未见纯合缺失；2)28例ALL中，5例发生异常甲基化；43例ANLL中，有7例发生了异常甲基化。结论p16基因缺失、异常甲基化可能与白血病的发生及预后有关。     

子宫内膜癌中p16基因缺失及CpG岛甲基化的研究

目的　研究子宫内膜癌中 p16基因缺失及CpG岛甲基化情况。 方法　用PCR技术检测 p16基因在子宫内膜癌中的纯合性缺失及第一外显子异常甲基化。结果　 36例癌组织中 9例发生基因缺失 ,12例发生甲基化 ,未发现基因缺失与甲基化同时存在的病例。结论　 1.p16基因缺失与子宫内膜癌组织学分级严重程度和临床分期呈正相关 ;2 .5’CpG甲基化可能是 p16基因失活的重要机理 ,参与子宫内膜癌发生、发展。     

子宫内膜癌p16／MTS1基因失活的研究

目的:探讨p16/MTS1基因在子官内膜癌组织的表达及意义.方法:采用显微切割-聚合酶链反应方法,对29例子宫内膜癌组织和癌旁正常组织中p16/MTS1基因纯合缺失进行检测.并用Fisher精确检验的方法,对p16/MTS1基因纯合缺失与临床病理关系进行统计分析.结果:29例子宫内膜癌组织,p16/MTS1基因纯合缺失率为24.14%.Ⅰ期纯合缺失率为24.00%,Ⅱ期纯合缺失率为33.33%.结论:p16/MTS1基因纯合缺失与子宫内膜癌的发生有关.     

子宫内膜癌p16/MTS1基因失活的研究

目的　探讨 p16 /MTS1基因在子宫内膜癌组织的表达及意义。 方法　采用显微切割 聚合酶链反应方法 ,对 2 9例子宫内膜癌组织和癌旁正常组织中 p16 /MTS1基因纯合缺失进行检测。并用Fisher精确检验的方法 ,对p16 /MTS1基因纯合缺失与临床病理关系进行统计分析。结果　 2 9例子宫内膜癌组织 ,p16 /MTS1基因纯合缺失率为 2 4.14 %。Ⅰ期纯合缺失率为 2 4.0 0 % ,Ⅱ期纯合缺失率为 3 3 .3 3 %。结论　p16 /MTS1基因纯合缺失与子宫内膜癌的发生有关。     

脑胶质瘤p 15 基因缺失及5′CPG 岛甲基化研究

 目的　探讨 p1 5基因变异及其与脑胶质瘤的发生、恶性进展的关系。方法　利用 PCR和 PCR- based甲基化检测技术检测了 56例脑胶质瘤中 p1 5基因外显子 1缺失及 5′CPG岛甲基化情况。结果　 43例高级别的脑胶质瘤中 ,1 4例发生了 p1 5基因缺失 ( 32 .6% ) ,而 1 3例低级别的脑胶质瘤中无一例发生 p1 5基因缺失 ,差异具有显著性 ( P<0 .0 5)。 1例低级别的脑胶质瘤、3例高级别的脑胶质瘤发生了 p1 5基因 5′CPG岛甲基化。结论　 p1 5基因异常可能参与脑胶质瘤的发生、恶性进展。基因纯合缺失是脑胶质瘤中 p1 5基因失活的主要机制.     

乳腺癌中P16基因缺失与突变的研究

背景与目的:了解乳腺癌与p16基因的关系.材料与方法:采用PCR和DNA测序方法,对33例乳腺癌患者肿瘤组织标本的p16基因进行检测,研究p16基因的缺失和突变情况.结果:所有标本均未检出纯合缺失,10例标本进行了外显子2的序列测定,也未发现点突变.结论:p166基因的纯合缺失和点突变可能与乳腺癌的发生无关.     

脑胶质瘤p15基因缺失及5′CPG岛甲基化研究

目的　探讨p15基因变异及其与脑胶质瘤的发生、恶性进展的关系。方法　利用PCR和PCR -based甲基化检测技术检测了5 6例脑胶质瘤中p15基因外显子 1缺失及 5′CPG岛甲基化情况。结果　 43例高级别的脑胶质瘤中 ,14例发生了p15基因缺失( 3 2 6% ) ,而 13例低级别的脑胶质瘤中无一例发生p15基因缺失 ,差异具有显著性 (P <0 0 5 )。 1例低级别的脑胶质瘤、3例高级别的脑胶质瘤发生了p15基因 5′CPG岛甲基化。结论　p15基因异常可能参与脑胶质瘤的发生、恶性进展。基因纯合缺失是脑胶质瘤中p15基因失活的主要机制。     

慢性粒细胞白血病急变与p16及降钙素基因关系的研究

目的　探讨p16基因纯合缺失、降钙素基因 (CT基因 )高度甲基化与慢性粒细胞白血病(CML)急变之间的关系。方法　分别采用半定量多重PCR、半定量PCR检测了 2 0例正常人和 5 3例CML患者p16基因纯合缺失和CT基因高度甲基化。结果　在 5 3例CML中 ,慢性期组、急粒变组、急淋变组、混合细胞急变组 ,p16基因纯合缺失、CT基因高度甲基化的阳性率分别为 0 % (0 / 2 0 )、6 2 %(1/ 16 )、6 6 7(8/ 12 )、40 0 % (2 / 5 )和 10 0 (2 / 2 0 )、6 8 8% (11/ 16 )、16 7% (2 / 12 )、40 0 % (2 / 5 )。结论CML急淋变、急粒变分别与p16基因纯合缺失、CT基因高度甲基化存在密切关系 ,而混合细胞急变与两种基因同时异常有关。同时检测这两种基因异常 ,有助于预测CML早期发生急变。     

p16及p15基因在子宫颈癌中的纯合性缺失及其临床意义

目的 :探讨抑癌基因p16、p15基因的纯合性缺失在子宫颈癌的发生发展中的作用。方法 :应用比较PCR技术检测 34例子宫颈癌组织和 2 0例正常宫颈组织中p16、p15基因的纯合性缺失。结果 :p16、p15基因的纯合性缺失率分别为 11 8%、14 7% ,p16、p15基因的纯合性缺失与组织学类型、临床分期及组织学分级无关。结论 :p16、p15基因的纯合性缺失在子宫颈癌的发生发展中可能起到一定的作用     

Infrequent CDKN2 (MTS1/p16) gene alterations in human primary breast cancer.

Changes which lead to excessive cyclin production or to loss of cell cycle inhibition by proteins such as p16/MTS1 may release breast tumour cells from the constraints of cell division. In order to establish the frequency of MTS1/p16 gene alteration and its relation with genetic damage to the p53 and cyclin D1 genes, we have studied these gene abnormalities in 164 human primary breast cancers and in six breast cancer cell lines. Two breast cancer cell lines and one primary tumour showed a homozygous deletion of exon 2 of the MTS1 gene. Using single-strand conformation polymorphism and subsequent sequencing analysis, one tumour showed an alteration at codon 67 (CCC-->CTC; Pro to Leu). Another tumour showed a mutation at codon 98 (without amino acid change) with an additional polymorphism at codon 140. This polymorphism was also found in 13 other tumour samples, but has no effect on (disease-free) survival. From these data we conclude that the occurrence of CDKN2 (p16/MTS1) mutation in primary breast cancer is a rare event and is not likely to be involved in human breast tumour carcinogenesis and progression.     

脑肿瘤p16基因缺失，突变及5’CpG岛甲基化研究

目的：探讨不同种类的脑肿瘤P16基因变异及其与脑肿瘤的发生,发展的关系。方法：利用PCR,PCR－SSCP及PCR－based甲基化技术检测了56例胶质瘤,15例脑膜瘤及2例原发性脑淋巴瘤P16基因缺失,突变及5’CpG岛甲基化状况,结果：18例高病理级别的脑胶质瘤及1例原发性脑淋巴瘤发生P16基因缺失;6例脑胶质瘤及1例原发性脑淋巴瘤发生P16基因5’CpG岛甲基化,无1例发生P16基因突变。结论：P16基因失活可能参与脑胶质瘤的发生,恶性进展及原发性脑淋巴瘤的发生,P16基因缺失是P16基因失活的主要机制。     

Primary malignant lymphoma of the brain: frequent abnormalities and inactivation of p14 tumor suppressor gene

Ten primary central nervous system lymphomas (PCNSL, brain lymphomas) were examined for p14 gene exon 1beta deletion, mutation and methylation by Southern blot analysis, nucleotide analysis of polymerase chain reaction clones and Southern blot-based methylation assay. In Southern blot analysis, from the signal densities of the hybridized bands and their similarities to those of exons 2 and 3 in our previous quantitative study, we found that exon 1beta was homozygously deleted in four cases, hemizygously deleted in five cases and not deleted in one case. Thus, the same deletion patterns covered the entire p14 gene for all cases except for one case, which suggested the hemizygous deletion of exons 1beta and 2 and homozygous deletion of exon 3. In addition, although exon 1beta mutation is rare in various tumors, we detected a missense mutation (L50R) in one case with a hemizygous deletion. Methylation of the 5'CpG island of the p14 gene was not suggested for any case without homozygous deletion. Our observation of frequent p14 gene abnormalities (90%) and inactivation (40-60%) was in striking contrast to the same pathological subtype of systemic lymphoma in which p14 gene abnormalities and inactivation were infrequent, suggesting a difference in carcinogenesis between PCNSL and systemic lymphoma.     

Homozygous deletion of p16INK4a and tobacco carcinogen exposure in nonsmall cell lung cancer

Inactivation of p16(INK4a) in the Rb pathway is among the most common somatic alterations observed in nonsmall cell lung cancers (NSCLCs). While epigenetic inactivation of the p16(INK4a) gene promoter has been shown to be associated with increased tobacco carcinogen exposure, little investigation of any similar association of homozygous deletion or mutation of p16(INK4a) and tobacco use has been completed. In 177 consecutive NSCLCs, we examined the determinants of p16(INK4a) homozygous deletion and mutation, including the pattern of tobacco smoking and asbestos exposure. We observed that p16(INK4a) homozygous deletion occurred at a higher frequency in never smokers as compared to former and current smokers (p = 0.01). This observation suggested that tumors from these patients might be more prone to DNA deletion events; consistent with this, epigenetic silencing of the DNA double-strand break repair genes FancF and BRCA1 was also associated with homozygous deletion of p16(INK4a)(p = 0.002 and p = 0.06, respectively). Finally, mutation of p16(INK4a) was rare and only occurred in patients who were smokers. Hence, the character of somatic alteration in the Rb pathway (deletion, mutation or methylation silencing) in NSCLC is associated with the pattern of tobacco exposure, suggesting that susceptibility to lung cancer is, at least in part, mediated by the biological mechanism that selects for the character of the induced somatic lesion.     

The role of p16-cyclin d/CDK-pRb pathway in the tumorigenesis of endometrioid-type endometrial carcinoma

We analysed p16 gene alteration and p16, cyclin-dependent kinase 4 (CDK4), CDK6, cyclin D1, cyclin D2, cyclin D3 and retinoblastoma protein (pRb) expression in ten normal endometriums (PE), 18 endometrial hyperplasias (EH) and 35 endometrial cancers (EC). Two of ten PE (20%), nine of 18 EH (50.0%) and 29 of 35 EC (82.9%) exhibited p16 nuclear staining. p16 expression was significantly higher in EC than EH (P = 0.0119). In the six p16 (-) EC, one was considered to have reduced gene dosage consistent with possible homozygous deletion of the CDKN2 gene and three had methylation in 5'CpG island in the promoter region of the p16 gene, whereas none showed such reduced gene dosage and four had methylation in the nine p16 (-) EH. Strong CDK4 staining was observed in 12 of 35 EC (34.3%) and one of 18 EH (5.6%). The strong expression of CDK4 was higher in EC than in EH (P = 0.0399). The expression of CDK4 was higher in EH than PE (P = 0.0054). The abnormalities of p16-cyclin D/CDK-pRb pathway were detected in 18 of 35 EC (51.4%). In conclusion, the expression of p16 and CDK4 may be an early event in the neoplastic transformation of endometrial cancer.     

原发恶性肿瘤MTS1／p16基因缺失的研究

目的:研究MTS1/p16基因在人类恶性肿瘤组织中的变化.方法:采用Southern杂交和多重PCR技术,分析了68例原发肿瘤组织标本,包括非小细胞肺癌31例、食管癌15例、胃癌13例、乳腺癌9例.结果:PCR检测癌旁组织未见p16基因缺失,而不同肿瘤组织标本的p16基因缺失差别很大,总缺失率为13.2%(9/68).Southern杂交检测p16基因的缺失率为17.7%(12/68).结论:MTS1/P16基因缺失在人类恶性肿瘤发生发展中起重要作用,是重要的多肿瘤抑制基因.     

乳腺癌MTS1/p16基因缺失及表达异常的初步研究

采用ＰＣＲ和免疫组化等方法对５１例乳腺肿瘤ＭＴＳ１／ｐ１６基因的缺失及表达异常情况进行了分析，结果显示，ＭＴＳ１／ｐ１６基因在乳腺癌中的阴性表达率为３２．６％（１５／４６），而其中６０％（９／１５）因纯合性缺失而无转录和表达产物，占总检测病例的１９．５％（９／４６）。ＭＴＳ１／ｐ１６基因缺失的病例多为淋巴结转移阳性，组织浸润程度高和分化程度低，提示ＭＴＳ１／ｐ１６基因的纯合性缺失与乳腺癌的发生发展及恶性程度密切相关。另外，在ｐ１６蛋白阴性表达的病例中除了基因的纯合性缺失造成的蛋白失表达外，还有４０％（６／１５）的病例有ＭＴＳ１／ｐ１６基因的扩增但没有表达产物，则可能是ＤＮＡ的异常甲基化，基因位移，点突变等其它基因变异作用的结果，进一步的研究正在进行中