p14ARF, p15INK4b and p16INK4a methylation status in chronic myelogenous leukemia

The INK4 family of proteins p15^INK4b, p14^ARF and p16^INK4a function as cell cycle inhibitors where they are involved in the inhibition of G1 phase progression. Methylation of the p15^INK4b promoter never seems to occur in solid tumors but is a major gene silencing mechanism in hematological malignancies. p14^ARF and p16^INK4a promoter methylation often occurs in solid tumors but also in leukemias and lymphomas. In chronic myelogenous leukemia (CML), only a few reports have been published regarding INK4 methylation and the results of the literature are discordant. Thus clearly, more works on large series have to be performed independently.     

High-density methylation of p14ARF and p16INK4A in Epstein-Barr virus-associated gastric carcinoma

Promoter hypermethylation of various tumor-related genes is extremely frequent in gastric carcinoma (GC) associated with Epstein-Barr virus (EBV). To investigate the significance of the promoter methylation in this type of GC, we examined the methylation densities of the promoter regions of p14ARF and p16INK4A in EBV-associated (n=7) and EBV-negative (n=14) GC. Bisulfite sequencing demonstrated a high frequency of concurrent methylation of p14ARF and p16INK4A promoter regions in EBVaGC. Methylation was observed in all 29 CpG sites of p14ARF and all 16 sites of p16INK4A with equally high densities. In EBV-negative GC, the methylation profiles differed between the 2 genes. Promoter methylation was sporadic and variable in p14ARF, and only the last position of CpG in p14ARF was methylated at high frequency. High-density methylation in p16INK4A was observed in a subset of GC, but the first position of CpG was never methylated in EBV-negative GC. These findings suggest the presence of mechanisms of de novo and maintenance methylation specific to EBVaGC that might be associated with EBV infection.     

非小细胞肺癌中P14ARF与P16INK4a和p53蛋白表达及其相互关系的研究

目的:检测p14ARF、p16INK4a和p53蛋白在非小细胞肺癌中表达情况,对它们在非小细胞肺癌发生过程中的作用及其相互关系进行初步探讨方法:应用免疫组化方法检测了40例非小细胞肺癌组织标本的p14AHF、p16INK4a和p53基因的表达水平.结果:非小细胞肺癌组织中p14ARF、p16INK4a和p53蛋白总阳性率分别是72.5%,50.0%和52 5%,与癌旁正常组织(分别是95.0%,92.5%,2.5%)有显著性差异(P＜0.01);非小细胞肺癌中p14ARF和p53蛋白表达异常与肿瘤分期、组织类型、分化程度、淋巴结转移情况无显著相关性;p16INK4a蛋白表达水平与组织分化程度相关(P＜0.05),但与肿瘤分期、组织类型、淋巴结转移情况无关;p14ARF和p53蛋白在组织中表达呈负相关,r2=-0.475(P＜0.0),而p14ARF和p16INK4a蛋白表达无关;p14ARF蛋白在Ⅰ期病例中强阳性( )占阳性比例为41.7%,在Ⅲ期中强阳性( )比例为10.0%.结论:p14ARF、p16INK4a和p53三个基因在NSCLC发生过程中起重要作用,特别在肿瘤早期可能起到更为重要的作用;p14ARF和p53基因在同一调节通路上;p14ARF、p16INK4a和p53蛋白可以作为非小细胞肺癌早期生物学检测指标.     

p16^INK4a和p14^ARF蛋白在宫颈癌和肺癌中的差异表达

[目的]研究宫颈癌和肺癌中p16INK4a和p14ARF蛋白表达水平的差异及意义。[方法]应用免疫组化方法检测50例宫颈癌和127例肺癌组织中p16INK4a和p14ARF蛋白表达。[结果]50例宫颈癌中,p16INK4a和p14ARF蛋白全部阳性表达;127例肺癌中,p16INK4a和p14ARF蛋白阳性表达率分别为61.42%和30.79%;宫颈癌和肺癌中p16INK4a和p14ARF蛋白表达差异均有显著性（P〈0.01）。[结论]p16INK4a和p14ARF蛋白在宫颈癌中过表达,而在肺癌中缺失表达。提示p16INK4a和p14ARF蛋白在宫颈癌和肺癌的发生发展中所起的作用和作用机制可能不同。     

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     

TP53, p14ARF,p16INK4a and H-ras gene molecular analysis in intestinal-type adenocarcinoma of the nasal cavity and paranasal sinuses

Intestinal-type adenocarcinoma (ITAC) of the nasal cavity and paranasal sinuses is an uncommon tumor associated with occupational exposure to dusts of different origin. Few investigations addressed molecular alterations in ITAC mainly focused on TP53, K-ras and H-ras gene mutations. The occurrence of TP53, p14(ARF) and p16(INK4a) deregulation and H-ras mutations was investigated in 21 consecutive and untreated ITACs cases, 17 with known professional exposure. No H-ras mutations were found. In patients with known exposure, cumulative evidence of TP53 or p14(ARF) alterations accounted for 88% and the evidence of p16(INK4a) alterations for 65%, respectively. TP53 mutations were present in 44% of the ITACs, consisted of G:C-->A:T transitions in 86%, and involved the CpG dinucleotides in 50% of the cases. LOH at the locus 17p13 and an uncommon high rate of p53 stabilization were detected in 58% and 59% of the cases, respectively. p14(ARF)and p16(INK4a) promoter methylation accounted for 80% and 67% respectively, and LOH at the locus 9p21 occurred in 45% of the cases. Interestingly, all dust-exposed tumors with p16(INK4a) alterations shared TP53 or p14(ARF) deregulation. The present results show a close association of this occupational tumor with TP53, p14(ARF) and p16(INK4a) gene deregulation. Given the important role that these genes play in cell growth control and apoptosis, the knowledge of ITAC genetic profile may be helpful in selecting more tailored treatments.     

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.     

Colorectal Cancers with both p16 and p14 Methylation Show Invasive Characteristics

Recent studies indicated that p16 and p14 inactivation owing to promoter methylation was important for colorectal tumorigenesis. In this study, we examined the methylation status of these genes in 86 primary colorectal cancers using methylation-specific PCR (MSP) and correlated the results with the clinicopathological features of the patients. Aberrant promoter methylation of p16 and p14 genes was detected in 43 of 86 (50%) and 25 of 86 (29%) colorectal cancers, respectively. Next, we examined the correlation of methylation status with the clinicopathological features. We found a significant difference in maximal tumor size ( P =0.022) when patients with both p16 and p14 methylation were compared to other patients. On the other hand, there was no significant difference in other factors, such as the extent of tumor and Dukes stage. These results suggested that colorectal cancer with both p16 and p14 methylation has the same invasiveness at a smaller size compared to that of the cancer with neither p16 nor p14 methylation. Inactivation of both p16 and p14 genes may result in a malignant change in colorectal cancer cells, leading to advanced cancers with a smaller size than those with p16 or p14 activity.     

p19~(ARF)和p16~(INK4a)在人骨肉瘤中表达的比较研究

目的比较p16INK4a和p19ARF两种抑癌基因在可切除的人骨肉瘤组织中的表达形式,探讨其在人骨肉瘤的发生、发展中的意义。方法人骨肉瘤切除石蜡标本37例,用单克隆抗体间接免疫荧光法同时测定肿瘤组织的p16、p19蛋白的表达。结果p16INK4a表达率56.8%(21/37),p19ARF表达率40.5%(15/37);p16与p19表达无相关性;p16和p19与骨肉瘤的外科分期、病理分级、血管浸润和肺部转移均无显著相关。结论p16、p19的下调都很可能是骨肉瘤发生发展的重要原因之一,未发现这两种抑癌基因之间的表达有显著关系。     

p16(INK4a) promoter methylation and protein expression in breast fibroadenoma and carcinoma

The potential role of p16(INK4a) methylation in breast cancer is controversial whereas there are no data on fibroadenoma. To assess if inactivation of p16(INK4a) by promoter hypermethylation occurs in this hyperproliferative benign breast lesion or, on the contrary, it is strictly related to the carcinogenic process, we have tested the different histological components of 15 cases of fibroadenoma and the intraductal and infiltrating components of 15 cases of carcinoma and their adjacent non-tumoral epithelium. All samples were obtained by laser-assisted microdissection. The relationship between promoter methylation status, immunohistochemical protein expression and ki67 proliferative activity was evaluated for each lesion. Our data demonstrate that hypermethylation of p16(INK4a) promoter is a common event occurring at similar frequency in all the different histological areas of the benign and malignant breast lesions taken into exam. Conversely, protein p16 expression, although heterogeneously distributed within the section, is considerably higher in breast carcinoma as compared to fibroadenoma in both tumoral and non-tumoral epithelia and stroma. The protein localization was almost exclusively nuclear in fibroadenoma and non-tumoral epithelia whereas, in carcinoma, the staining was both nuclear and cytoplasmic or cytoplasmic alone. Furthermore, in a subset of fibroadenoma with higher proliferative activity, p16 protein expression was substantially decreased as compared to those showing lower proliferation. We did not observe this association in carcinomas. Our data demonstrate that the hypermethylation of the p16(INK4a) promoter is not specifically associated with malignancy and that, on the contrary, the overexpression of p16 and its cytoplasmic sequestration is a feature of breast carcinoma.     

p16INK4a在宫颈液基细胞学辅助筛查中的标记意义

目的 评价p16INK4a在宫颈液基细胞学检查中的标记意义.方法 收集74例宫颈外口和颈管的脱落细胞标本,分别进行液基细胞学检测和p16INK4a免疫细胞化学染色,并应用杂交捕获二代法检测高危人乳头瘤病毒(HR-HPV)感染.结果 74例标本中,细胞学诊断未见癌细胞或癌前病变细胞(阴性)10例,意义不明的不典型鳞状细胞(ASC-US)15例,鳞状上皮内低度病变(LSIL)28例,不除外上皮内高度病变的不典型鳞状细胞(ASC-H)5例,鳞状上皮内高度病变(HSIL)11例,鳞状细胞癌(SCC)5例.各级别病变中,HR-HPV阳性者分别为1、4、3、9、7和5例,p16INK4a免疫细胞化学染色阳性者分别为2、5、3、8、9和5例.随着宫颈病变级别的上升,HR-HPV和p16INK4a免疫细胞化学染色阳性率均增高.结论 p16INK4a免疫细胞化学染色增强了对不典型细胞的区分能力,可以提高宫颈癌筛查的准确性.     

大鼠肺鳞癌中p16INK4a和p19ARF基因的缺失研究

目的研究p16INK4a和p19ARF基因的缺失与大鼠肺鳞癌发生发展的关系.方法利用显微切割和聚合酶链反应(PCR)技术,在10例正常大鼠支气管黏膜上皮细胞、16例癌前病变细胞和34例肺鳞癌组织分别检测p16INK4aE1α和p19ARFE1β的缺失.结果10例大鼠正常支气管黏膜上皮细胞均未发现有p16INK4aE1α和p19ARFE1β的缺失.在16例癌前病变中发现p16INK4aE1α和p19ARFE1β缺失的检出率分别为12.50%(2/16)和6.25%(1/16);p16INK4aE1α或(和)p19ARFE1β总缺失率为18.75%(3/16).34例大鼠肺鳞癌中p16INK4aE1α和p19ARFE1β缺失的检出率分别为32.35%(11/34)和41.18%(14/34),其中有9例两者同时缺失,p16INK4aE1α或(和)p19ARFE1β总缺失率为47.06%(16/34).肺鳞癌的p19ARFE1β的缺失率显著高于癌前病变,P=0.012.结论在诱发性大鼠肺鳞癌的发生发展中,p16INK4a基因的缺失可能在早期已起作用,p19ARF的生物学活性可能强于p16INK4a.p16INK4a和p19ARF基因的同时缺失损伤了Rb和p53 2条肿瘤抑制途径,这可能有助于大鼠肺鳞癌的恶性进展.     

食管鳞癌中p16基因启动子区甲基化及其表达

 目的探讨食管鳞癌（ESCC）p16基因甲基化的状况及其表达与食管鳞癌临床病理特征之间的关系。方法采用甲基化特异性PCR方法（MSP）分别检测75例食管癌组织、癌旁组织和切缘组织p16基因启动子区域CpG岛甲基化状态。采用Envision免疫组化法检测食管癌组织及癌旁组织的p16蛋白的表达。结果75例标本中，食管癌组织、癌旁组织和切缘细织p16基因甲基化率分别为41．3％（31／75）、13．3％（10／75）和6．67％（5／75）。癌组织和癌旁组织P16蛋白的阳性表达率分别为29．3％（22／75）和56．7％0（17／30）。31例癌组织p16基因甲基化阳性标本中有2例（6．4％）检测到P16蛋白的表达，而44例癌组织p16基因甲基化阴性标本中有20例（45．5％）检测到P16蛋白的表达。食管癌组织p16基因甲基化率显著高于癌旁组织和切缘组织（P〈0.01），P16蛋白表达与p16基因甲基化呈负相关。p16基因启动子区甲基化与食管癌的组织学分级、肿瘤部位无明显相关，与临床分期、淋巴转移密切相关。结论p16基因甲基化在食管癌发生发展中起着重要作用，食管鳞癌的分期和淋巴结转移与p16基因甲基化之间有密切关系。     

Immunohistochemical analysis of p16INK4a,p14ARF,p18INK4c,p21CIP1, p27KIP1 and p73 expression in 271 meningiomas correlation with tumor grade and clinical outcome

Routine pathological examination cannot distinctively predict the clinical course of meningiomas because even histologically benign tumors may recur after gross total resection. Numerous efforts have been made for the evaluation of different immunohistochemical assays in meningioma prognosis. We investigated the prognostic significance of p16INK4a, p14ARF, p18INK4c, p21CIP1, p27KIP1 and p73 expression by immunohistochemical analysis of 271 meningiomas. All tumors were additionally stained for the proliferation markers Ki-67 and DNA topoisomerase II alpha (TopoIIalpha). Significant differences between the number of p16INK4a-, p18INK4c- and p21CIP1-positive cases were noted among the 3 grades of meningiomas. p16INK4a- and p21CIP-positive tumors were found to prevail among benign meningiomas, whereas p18INK4c immunostaining was closely associated to anaplastic meningiomas. The number of p16INK4a- and p21CIP-positive cases was significantly lower in the cohort of recurrent meningiomas. In contrast, p18INK4c-positive cases were clustered among recurrent meningiomas regardless of tumor grade. Immunoreactivity of p14ARF, p27KIP1 and p73 did not show any differences between meningiomas of various histology and clinical outcomes. Multivariate analysis revealed that only tumor grade and TopoIIalpha index are independent criteria for predicting meningioma recurrence. Thus, the immunohistochemical assessment of p16INK4a, p14ARF, p18INK4c, p21CIP1, p27KIP1 and p73 expression in meningiomas does not appear to provide prognostically useful information. Further studies are needed to identify more reliable prognostic markers and to address in more detail the role of cell cycle aberrations in these tumors.     

INK4/ARF germline alterations in pancreatic cancer patients.

BACKGROUND: Roughly 40% of germinal mutations in melanoma families (MF) affect p16(INK4a) and p14(ARF). We investigated the association between INK4/ARF alterations and the occurrence of pancreatic cancer in MF and in sporadic pancreatic cancer (SPC) patients. PATIENTS AND METHODS: Forty-nine MF, 66 SPC cases and 54 controls were enrolled. The INK4/ARF locus was screened. RESULTS: As compared with the general population, the risk of pancreatic cancer (PC) was increased 9.4-fold [95% confidence interval (CI) 2.7-33.4] and 2.2-fold (95% CI 0.8-5.7) in G101W-positive and -negative MF, respectively, while mean ages at onset were 61 and 77 years, respectively. A 1.7 (95% CI 1.06-2.79) increased risk of cancer at any site was observed among first-degree relatives of SPC cases as compared with controls. The G101W founder mutation was detected in 4% of SPC cases but the rate increased to 13% when tumor clustering in either branch of families was taken into account. One G101W-positive PC patient with a melanoma in a first-degree relative harbored a germline deletion of the second allele, including exon 1B. CONCLUSIONS: The presence of a deletion including exon 1B in two PC patients points to the involvement of p14(ARF) in the development of PC and may suggest that the increased risk of PC in MF is caused by impairment of both loci.     

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     

结肠癌组织中p16/MTS1基因5′CpG岛甲基化研究

:〔目的〕研究结肠癌组织中p16基因5′端CpG岛异常甲基化现象。〔方法〕采用甲基化特异PCR方法(MSP)检测了28例结肠癌和20例癌旁正常组织标本。〔结果〕28例结肠癌组织中有9例5′端CpG岛异常甲基化(32%),而20例正常组织中均阴性。〔结论〕p16基因5′端CpG岛异常甲基化在人类结肠癌的发生中可能起一定作用。     

Role of P14 and MGMT Gene Methylation in Hepatocellular Carcinomas: a Meta-analysis

Background: This meta-analysis was performed to investigate the relationship between methylation of the P14 and O6-methylguanine-DNA methyltransferase (MGMT) genes and the risk of hepatocellular carcinoma (HCC). Materials and Methods: We searched PubMed, EMBASE, the Chinese Biomedical Database (CBM), and the China National Knowledge Infrastructure (CNKI) databases to identify relevant studies that analysed HCC tissues for P14 and MGMT gene methylation status; we then performed a meta-analysis. Odds ratios (ORs) and95% confidence intervals (95%CIs) were calculated to evaluate the association between gene methylation and the risk of HCC. Results: Ten studies that assessed P14 gene methylation in 630 HCC tumour tissues and nine studies analysing MGMT methylation in 497 HCC tumour tissues met our inclusion criteria. Our meta-analysis revealed that the rate of P14 methylation was significantly higher in HCCs than in adjacent tissues (OR 3.69, 95%CI 1.63-8.35, p=0.002), but there was no significant difference in MGMT methylation between HCC and adjacent tissues (OR 1.76, 95%CI 0.55-5.64, p=0.34). A subgroup analysis according to ethnicity revealed that P14 methylation was closely related to the risk of HCC in Chinese and Western individuals (Chinese, OR 7.74, 95%CI 1.36-44.04, p=0.021; Western, OR 3.60, 95%CI 1.49-8.69, p=0.004). Furthermore, MGMT methylation was not correlated with the risk of HCC in Chinese individuals (OR 2.42, 95%CI 0.76-7.73, p=0.134). The combined rate of P14 methylation was 35% (95%CI 24-48%) in HCC tumour tissues and 11% (95%CI 4-27%) in adjacent tissues, whereas the combined rate of MGMT methylation was 15% (95%CI 6-32%) in HCC and 10% (95%CI 4-22%) in adjacent tissues. Conclusions: These results suggest that the risk of HCC is related to P14 methylation, but not MGMT methylation. Therefore, P14 gene methylation may be a potential biomarkerfor the diagnosis of HCC.     

HYPERMETHYLATION STATUS OF E-CADHERIN AND p16^INK4a IN GASTROINTESTINAL STROMAL TUMOR

Objective： To investigate the methylation status of CpG island in E-cadherin（CDHl）, P16^INK4a（ P16）promoter region ,and to analyze their role in gastrointestinal stromal rumor （GISTs）. Methods： A total of 56 surgically resected GISTs were obtained from January 2003 to December 2005. The routine H＆E-stained sections and CD117, CD34-immunoreactions were reviewed to verify the morphologic diagnosis. Methylation status of the CDH1, P16^INK4a promoter region was analyzed by methylation specific polymerase chain reaction （MSP） from chemically modified DNA after Na-bisulfite treatment. Results： The frequency of CDHlgene methylation was 32% （18 of 56） in GISTs. The rate was 9% （1 of 11）, 21% （4 of 19）, 41.6% （5 of 12）, and 57% （8 of 14） for very low risk, low risk, intermediate risk, and high risk GISTs; P16^INK4a methylation was found in 19 of 56（34%） cases. The rate was 0% （0 of 11）, 16% （3 of 19）, 50% （6 of 12）, and 71% （10 of 14） for very low risk, low risk, intermediate risk, and high risk GISTs. Statistical analysis indicated that of the 56 cases, there was significant association of CDH^INK4a and/or P16^INK4a methylation status with tumor malignant behavior （methylation rate 23/56, 41%, P〈0.01） and site （P〈0.05）. Conclusion： E-cadherin （CDHI） and/or P16^INK4a promoter hypermethylation is strongly associated with risk grade, may be a useful biomarker for GISTs risk assessment, and may shed light on new therapeutic options to treat GISTs