细胞周期抑制蛋白p16INK4a在宫颈病变中的异常表达

[目的]探讨宫颈癌(UCC)、宫颈上皮内瘤变(CIN)及宫颈炎中p16INK4a蛋白表达水平的变化及意义.[方法]应用免疫组化方法检测126例宫颈病变(UCC 50例、CIN 57例和宫颈炎19例)组织中p16INK4a蛋白的表达,进行半定量分析及统计学检验.[结果]50例UCC中,p16INK4a全部阳性表达;57例CIN中,p16INK4a阳性表达41例.阳性表达率为71.93%,其中CINⅠ,CINⅡ CINⅢ p16INK4a阳性表达率分别为36.84%(7/19)、81.82%(18/22)、100.00%(16/16),且三者间差异有显著性(P＜0.05).19例宫颈炎组织中,p16INK4a阳性表达8例,阳性表达率为42.11%.p16INK4a蛋自在宫颈炎、CIN和UCC组织中表达水平依次升高,且差异有显著性(P＜0.05).[结论]UCC及癌前病变中p16INK4a阳性表达明显高于良性病变.p16INK4a在UCC及癌前病变中过表达,提示其在UCC发生、发展中起重要作用.     

宫颈癌及其癌前病变组织中p16INK4a和PCNA的表达及临床意义

目的：探讨p16^INK4a、增殖细胞核抗原（proliferating cell nuclear antigen,PCNA）在宫颈癌及其癌前病变组织中的表达及临床意义。方法：采用免疫组化SP法检测p16^INK4a和PCNA在40例宫颈癌、33例宫颈上皮内瘤样变（cervical intraepithelial neoplasia,CIN）Ⅱ-Ⅲ、28例CINⅠ和10例正常宫颈组织标本中的表达。结果：1）p16^INK4a在正常宫颈组织中无表达。宫颈癌或CINⅡ-Ⅲ的p16^INK4a表达阳性率显著高于CINⅠ,P〈0.01。CINⅠ、CINⅡ-Ⅲ和宫颈癌PCNA表达阳性率显著高于正常宫颈,P〈0.01。p16^INK4a、PCNA表达强度随着宫颈病变程度的加重而增高,P〈0.001。2）宫颈癌不同组织学类型、病理组织分级和临床分期p16^INK4a表达阳性率及表达强度差异均无统计学意义,P〉0.05。在不同病理组织分级和临床分期中PCNA表达强度呈增强趋势,差异有统计学意义,P〈0.05。3）p16^INK4a、PCNA在CINⅠ和CINⅡ-Ⅲ组织中的表达均呈显著正相关,P〈0.01。结论：CINⅠp16^INK4a阳性表达是其发生质变的信号,PCNA可作为宫颈细胞异常增殖的灵敏标志。联合检测宫颈病变组织中p16^INK4a和PCNA的表达有助于对宫颈癌前病变进行早期诊断。     

p16蛋白在胃癌组织中的表达及其临床意义

ｐ16基因是新近发现的 1种抑癌基因 ,其突变或缺失与多种肿瘤的发生有关[1～ 4 ] 。我们采用免疫组化Ｓ Ｐ法 ,观察胃癌及癌旁组织中 ｐ16基因的蛋白表达水平 ,以探讨ｐ16基因在胃癌发生中的意义。1　材料和方法1.1　材料选取我院 1997年 1月至 1999年 10月手术切除的胃癌组织标本 88例。男性患者 5 3例 ,女性 35例 ,年龄 32～ 6 9岁。所有患者术前均未行化疗和放疗。按ＷＨＯ标准分类 ,中、高分化2 7例 ,低分化 6 1例。 5 2例癌旁组织为远离癌灶 2ｃｍ以上的正常胃组织。ｐ16单克隆抗体及即用型Ｓ Ｐ试剂盒均购自北京中山生物技术公司。1.2…     

p16蛋白在直肠癌组织中的表达及其临床意义

近年来国内外学者经过大量研究发现 ,ｐ16基因及其编码合成的ｐ16蛋白的生物学功能与细胞增殖周期关系密切 ,是细胞增殖的负调控因子。其缺失在很多肿瘤的形成和发展中起重要作用 ,且在不同肿瘤组织中的表达各不相同。为探讨ｐ16蛋白在直肠癌组织中的表达及其临床意义 ,我们设计并进行了以下研究。一、材料与方法1 一般资料 :收集我院 1997～ 1999年间资料完整的直肠癌术后石蜡包埋标本 5 7例 ,取其中 46例距肿瘤下边缘 2ｃｍ以内的直肠组织标本作为癌旁对照 ;同时对 2 0例非直肠癌患者的正常直肠组织进行检测。在 5 7例直肠癌中 ,高中分化…     

p16蛋白在胃癌组织中的表达及其临床意义

我们应用免疫组织化学法观察了ｐ16蛋白在胃癌组织及胃良性疾病、正常胃组织中表达情况,以探讨ｐ16蛋白在胃癌发生发展中的作用及其临床意义。一、材料与方法1研究对象:试验组收集手术切除胃癌蜡块标本50例。对照组为胃良性疾病15例,正常胃粘膜组织10例。均经病理证实。2方法:兔抗ｐ16多克隆抗体试剂盒购自北京中山生物技术公司。免疫组化方法参照试剂盒说明进行。每批设已知ｐ16阳性染色的乳腺癌组织为阳性对照,用ＰＢＳ代替一抗作为阴性对照。3阳性判断及统计学处理:胞浆内出现棕黄色颗粒为阳性,胞浆无棕色为阴性。结果用χ2检验。二、结…     

非小细胞肺癌p14ARFp16INK4a蛋白共表达及其临床意义

目的:探讨p14ARF、p16INK4a蛋白在非小细胞肺癌(NSCLC)组织中的表达、意义及相关关系.方法:采用免疫组织化学SP方法对103例NSCLC组织中p14ARF和p16INK4a蛋白的表达进行检测.结果:103例NSCLC组织中p14ARF、p16INK4a蛋白表达阴性率分别为70.87%和43.69%,差异有显著性(P＜0.01).其中35例p14ARF、p16INK4a蛋白表达共阴性,共阴性率达33.98%(35/103),鳞癌中共阴性率明显高于其它组织类型(P＜0.01).p14ARF、p16INK4a蛋白表达阴性相互间无显著相关性(P＞0.05).临床Ⅲ Ⅳ期病例两种蛋白表达阴性率明显高于临床Ⅰ Ⅱ期(P＜0.05).结论:NSCLC组织p14ARF、p16INK4a蛋白表达共阴性具有明显的组织学类型特异性,两种蛋白阴性表达是各自独立的事件.     

p16INK4a和Ki67在胃癌及癌前病变中的表达和意义

目的:探讨p16INK4a、Ki67在慢性胃炎、胃上皮内瘤变、胃癌及癌旁非肿瘤性胃黏膜中的表达和临床意义。方法:采用免疫组织化学SP法检测23例慢性胃炎、16例胃低级别上皮内瘤变、16例胃高级别上皮内瘤变、45例胃癌及癌旁非肿瘤性胃黏膜组织样本中p16INK4a、Ki67的表达。结果:p16INK4a在慢性胃炎、低级别上皮内瘤变、高级别上皮内瘤变和胃癌细胞中均呈核浆型表达,阳性表达率分别为4.34%、25.00%、62.50%、66.67%,在癌旁非肿瘤性胃黏膜腺体上皮细胞中呈阴性表达;Ki67在慢性胃炎、低级别上皮内瘤变、高级别上皮内瘤变和胃癌组织细胞中呈核型表达,Ki67指数分别为17.39%、37.50%、56.25%和77.78%。结论:p16INK4a代偿性高表达是胃癌和胃癌前病变的重要免疫表型特征,联合检测p16INK4a和Ki67表达可作为胃癌诊断的分子靶标和可靠方法。     

p16蛋白在肺癌中的异常表达及临床意义

目的研究ＭＴＳ１基因产物ｐ１６蛋白异常表达与肺癌发生、发展的关系。方法利用免疫组织化学ＡＢＣ法对４１例肺癌和３０例癌旁正常肺组织中ｐ１６蛋白的表达进行研究。结果ｐ１６蛋白多呈胞浆表达,少量核膜或核表达。肺癌组织中ｐ１６蛋白总阳性率为５１２％,低于癌旁组织ｐ１６阳性率（９０％）（χ２＝１１９,Ｐ＜０００５）。病理分型间ｐ１６蛋白表达未发现显著性差异（Ｐ＝０８４６６）。肺癌病理分级Ⅰ～Ⅱ级ｐ１６蛋白表达率高于Ⅲ级（χ２＝６４９,Ｐ＜００５）。ｐ１６蛋白表达水平与临床分期呈负相关（ｒ＝－０９８４,Ｐ＜０００１）。转移性肺癌ｐ１６蛋白表达水平显著低于非转移性肺癌（Ｐ＝０００３１）。结论ｐ１６蛋白表达缺失与低表达与肺癌的发生、发展与分化程度密切相关,ｐ１６蛋白表达缺失多是肺癌的晚期表现。     

p16、p27蛋白在子宫颈癌中的表达及临床意义

[目的]研究p16、p27蛋白在子宫颈癌发生发展中的作用及其临床意义。[方法]采用单克隆抗体SP免疫组化技术对54例子宫颈癌和20例正常宫颈组织进行p16、p27蛋白表达检测。[结果](1)p16、p27蛋白在子宫颈癌与正常宫颈组织中的阳性表达分别为48.15%、95%和40.7%、100％，其差异有极显著性（P＜0.01)。（2）p16蛋白在中、高分化组中的表达率高于低分化组，差异具显著性（P＜0.05)，p16、p27表达明显与组织分化程度相关（P＜0.01)。（3）p16、p27表达与盆腔淋巴结转移及预后有关（P＜0.05)。[结论]p16、p27蛋白表达可作为子宫颈癌恶性程度的指标，可为正确估计宫颈癌的预后、指导基因治疗提供依据。     

Alterations of the p16(INK4) locus in human malignant mesothelial tumors

The INK4 locus has two promoters and encodes two unique proteins that share exons in different reading frames, p16(INK4a) and p14(ARF). The p16(INK4a) protein, by inhibiting cyclin-dependent kinase, down regulates Rb-E2F and leads to cell cycle arrest in the G1 phase. The p14(ARF) protein interacts with the MDM2 protein, neutralizing MDM2-mediated degradation of p53. Since p53/Rb genes are not altered in malignant mesothelioma, additional components of these pathways, such as p16(INK4a) and p14(ARF), are candidates for inactivation. In this study, we have examined p16(INK4a) and p14(ARF) alterations (gene deletion, mutation and promoter methylation) in 45 primary malignant mesothelioma specimens. Fourteen patients (31%) had altered p16; four tumors had a methylated promoter region (8.8%), 10 tumors showed p16 to be deleted (22.2%), and one tumor had a point mutation (2%). We did not find any instances of methylation in the p14(ARF) 5'-CpG island. Patients whose tumors had p16 deletion were significantly younger than those with methylation, and, in the patients whose lungs were studied for the prevalence of asbestos fibers, those with any p16 alteration had lower fiber counts than those with no p16 alteration. Hence, p16 gene alteration is relatively common in malignant mesothelioma, while p14(ARF) is rarely, if ever, methylated. Our data suggest that deletion of p16 occurs in a relatively susceptible subset of the population.     

p15INK4b, p14ARF, and p16INK4a inactivation in sporadic and neurofibromatosis type 1-related malignant peripheral nerve sheath tumors.

PURPOSE: Malignant peripheral nerve sheath tumor (MPNST) can arise sporadically or in association with neurofibromatosis type 1. Deletions at the 9p21 locus have been reported in these tumors. To additionally characterize the status of this chromosomal region, in this study we performed a comprehensive, mostly PCR-based molecular analysis of the three tumor suppressor genes p15(INK4b), p14(ARF) and p16(INK4a) located at the 9p21 locus in 26 cryopreserved MPNSTs. EXPERIMENTAL DESIGN: Fourteen neurofibromatosis type 1-related and 12 sporadic cases were investigated for homozygous deletion coupled with fluorescent in situ hybridization, promoter methylation, and mutational analysis, as well as m-RNA expression. RESULTS: The results showed that an inactivation of one or more genes occurred in 77% of MPNSTs and was mainly achieved through homozygous deletion (46%), which, in turn, encompassed all of the three tandemly linked genes in 83% of the deleted cases. Promoter methylation was at a less extent involved in gene silencing (18%), and no mutations were found. Loss of function at DNA level strongly correlated with loss of mRNA expression accounting for 80% of the cases. Because of the close relationship between p14(ARF) and TP53 and between p15(INK4b)/p16(INK4a) and Rb, these results support a model of a coinactivation of TP53 and Rb pathways in 75% of MPNSTs, with functional consequences on cell growth control and apoptosis. CONCLUSIONS: The inactivation of the 9p21 locus is a frequent and peculiar hallmark of MPNST genetic profile leading also to an impaired apoptosis that could be taken into account in treatment planning of these tumors.     

Inactivation of p16INK4a expression in malignant mesothelioma by methylation

The molecular mechanisms of oncogenesis in mesothelioma involve the loss of negative regulators of cell growth including p16(INK4a). Absence of expression of the p16(INK4a) gene product is exhibited in virtually all mesothelioma tumors and cell lines examined to date. Loss of p16(INK4a) expression has also been frequently observed in more common neoplasms such as lung cancer as well. In a wide variety of these malignancies, including lung cancer, p16(INK4a) expression is known to be inactivated by hypermethylation of the first exon. In a survey of ten mesothelioma cell lines, one cell line (NCI-H2596) was identified as possessing loss of p16(INK4a) gene product following gene methylation. This methylation in these mesothelioma cells could be reversed, resulting in re-expression of p16(INK4a) protein, following the treatment of the cells with cytidine analogs, which are known inhibitors of DNA methylation. In previous clinical trials in mesothelioma, the cytidine analog dihydro-5-azacytidine (DHAC) has been found to induce clinical responses in approximately 17% of patients with mesothelioma treated with this drug, including prolonged complete responses. In addition, we identified evidence for methylation of p16(INK4a) in three of 11 resected mesothelioma tumor samples. When both cell lines and tumors are combined, inactivation of p16(INK4a) gene product expression following DNA hypermethylation was found in four of 21 samples (19%). We are further exploring the clinical significance of inhibition of methylation in mesothelioma by cytidine analogs. This may provide a potential treatment target in some mesothelioma tumors by inhibition of methylation.     

Deletion and differential expression of p16INK4a in mouse lung tumors

Recent allelotyping of chemical-induced lung tumors in hybrid mice has detected loss of heterozygosity on chromosome 4 in a region involving the interferon-alpha (IFN-alpha gene cluster that is syntenic to human chromosome 9p21-22, the location of the p16INK4a (p16) and p15INK4b (p15) tumor suppressor genes. The purpose of the current investigation was to characterize the expression of p16 and p15 in lung tumors and tumor-derived cell lines induced in A/J mice by exposure to the tobacco- specific nitrosamine, 4-methylnitrosamino-1-(3-pyridyl)-1-butanone (NNK). Expression of p16 and p15 was detected in all primary lung tumors; however, levels of expression of p16 differed by up to 15-fold between tumors. This is the first study to note a marked difference in the expression of the p16 gene in primary lung tumors. The apparent low levels of expression seen in approximately half of the tumors was not attributed to deletion, mutation or methylation of the p16 gene. Conversely, the high levels of p16 expression were not the result of effects on the retinoblastoma gene (Rb) or cyclin D1 proteins but most likely in response to a dysfunction elsewhere within this pathway. In contrast to the detection of p16 expression in primary tumors, this gene was deleted in all four cell lines. Three of four cell lines also showed loss of the p15 gene. Mapping of these homozygous deletions on chromosome 4 revealed that the p16 gene resides near the D4MIT77 marker, which is located approximately 12 cM proximal to the IFN-alpha gene cluster, thereby implicating the p16 gene as one of the targets within the allelic deletions detected previously in primary lung tumors from hybrid mice.      

pRB, p53, p16INK4a, senescence and malignant transformation

Recent works aimed at clarifying the respective roles of p16INKa and p14ARF (both located on the same INK4a locus on chromosome 9p21 in man) in malignant transformation come to the conclusion that p16INK4a is the true tumor suppressor gene in man. In mouse, it is the p19ARF knockout that suppresses the barrier protecting cells from malignant transformation. This situation is in agreement with p19ARF- and p16-mediated senescence induced by oncogenic mutated ras (Ras*) in mouse and man respectively. Other results have shown that senescence in human diploid fibroblasts is associated with heterochromatin occurrence that maintains in repressed state E2F1-induced gens required for G1 to S phases transition. Since RB protein is responsible for this chromatin modification, cells with any impaired RB pathway cannot enter into senescence.     

肺癌p14ARF和p16INK4a基因协同表达缺失及其意义

目的：研究抑癌基因位点ＩＮＫ４ａ－ＡＲＦ在肺肿瘤细胞中的表达状况,揭示ｐ１４ＡＲＦ和ｐ１６ＩＮＫ４ａ协同表达缺失与肺癌发生发展的相关性。方法：用ＲＴ－ＰＣＲ和Ｗｅｓｔｅｒｎ ｂｌｏｔ对６株肺癌细胞（ＳＰＣ－Ａ－１,Ｃａｌｕ－１,Ｈ４４６,ＳＨ７７,Ａ５４９,Ｈ４６０）的ＩＮＫ－４ａ－ＡＲＦ基因位点在ｍＲＮＡ、蛋白水平上进行检测,对ＰＣＲ产物进行纯化和测序分析。结果：６株肺癌细胞中,有３株细胞（Ｈ４     

Aberrations of p16INK4A,p14ARF and p15INK4B genes in pediatric solid tumors

Expression of the p16INK4A (p16), p15INK4B (p15), and p14ARF genes, located at 9p21, was examined in pediatric neuroblastoma (NB), Ewing's sarcoma (ES), and rhabdomyosarcoma (RMS). p16 expression was absent in 4 of 5 ESs, and 2 of these 4 cases died. p16 expression was reduced or absent in 10 of 12 RMSs, and 4 of these 10 cases died. These results suggested the possibility that p16 expression was associated with the progression of ES and RMS. There has been no previous report on p14ARF in NB. Our investigation might indicate that abnormal expression of the p16 and p14ARF was associated with a poor prognosis in NB, although in some cases of NB normal p16 and abnormal p14ARF expression was seen. These findings suggest an important role of p14ARF gene in the tumorigenesis of NB. The different incidence of expression of the p16, p15, and p14ARF genes in these 3 tumor types may reflect differences of the molecular process through which the 3 tumors develop. Our results suggest that abnormal expression of the p16 and/or p14ARF may be associated with a poor prognosis in these 3 tumors.     

宫颈脱落细胞p16INK4A和p57KIP2表达及其临床意义的初步探讨

目的:研究p16INK4A和p57KIP2在宫颈脱落细胞的表达及其与临床病理指标的关系。方法:采用免疫细胞化学二步法,检测81例不同病变阶段的宫颈脱落细胞标本中p16INK4A和p57KIP2的表达。结果:p16INK4A在ASC-US、低级别上皮内病变(CINⅠ)、高级别上皮内病变(CINⅡ～Ⅲ)和浸润性癌的阳性表达率分别为6.25%(1/16)、58.8%(10/17)、89.2%(33/37)和100.0%(11/11),各组之间的差异有统计学意义,χ2=38.806,P<0.001;p57KIP2在高级别上皮内病变(CINⅡ～Ⅲ)和浸润性癌的阳性表达率为27.1%(13/48),与ASC-US和低级别上皮内病变(CINⅠ)的阳性表达率为69.7%(23/33)比较,差异有统计学意义,χ2=15.194,P=0.002。结论:p16INK4A和p57KIP2在宫颈脱落细胞中的表达与临床病理指标密切相关,p16INK4A和p57KIP2可以作为宫颈癌前病变高危人群的筛查指标。     

人脑胶质瘤组织p57^kip2和P16蛋白表达及其临床意义的研究

目的：探讨p57^kip2蛋白、p16蛋白在人脑胶质瘤组织中的表达及其临床意义。方法：采用免疫组织化学SP法检测p57^kip2、p16在55例人脑胶质瘤和10例正常脑组织中的表达。结果：在55例胶质瘤组织中,p57^kip2蛋白阳性率为38．2％（21／55）,显著低于正常脑组织80．0％（8／10）,P=0．014。p57^kip2蛋白表达在低度恶性（Ⅰ～Ⅱ级）组显著高于高度恶性（Ⅲ～Ⅳ级）纽,P=0．029;生存时间≥2年组显著高于〈2年组,P=0．082。脑胶质瘤组织中p16蛋白表达阳性率为SO．9％（28／SS）,与正常脑组织相比差异无统计学意义,P=0．051。p16蛋白表达在高度恶性（Ⅲ～Ⅳ级）组显著高于低度恶性（Ⅰ～Ⅱ级）组（P=0．022）,生存时间〈2年组显著低于≥2年组,P=0．040。p57^kip2蛋白的表达与p16蛋白的表达存在正相关,rs=0．888,P=0．003。结论：p57^kip2蛋白和p16蛋白在脑胶质瘤中存在异常表达,p57^kip2蛋白和p16蛋白的表达程度与脑胶质瘤的分化程度和预后相关。