APC gene mutations in Chinese familial adenomatous polyposis patients

AIM:To study the characteristics of APC(adenomatous polyposis coli)gene germline mutation in Chinese patients with familial adenomatous polyposis(FAP).METHODS:APC gene from 14 FAP families was amplified by polymerase chain reaction(PCR)and underwent direct sequencing to determine the micromutation type.For the samples without micromutation,the large fragment deletion of APC gene was examined by multiplex ligation-dependent probe amplification(MLPA).RESULTS:There were gene micromutations in 9 families with a micromutation detection rate of 64.3%(9/14),including 6 frameshift mutations(66.7%),1 nonsense mutation(11.1%)and 2 splicing mutations(22.2%).Large fragment deletions were detected by MLPA in 2 families.The total mutation detection rate of micromutations and large fragment deletions was 78.6%(11/14).CONCLUSION:The detection rate of APC gene germline mutation can be improved by direct sequencing combined with MLPA large fragment deletion detection.

Deficiency of Adenomatous Polyposis Coli protein in sporadic colorectal adenomas and its associations with clinical phenotype and histology

瞄准：评估腺瘤结肠息肉病(APC ) 蛋白质的损失的频率并且把 APC 地位与颜色的特征作比较表面的腺瘤。方法：APC 蛋白质的 Immunohistochemical 分析在 118 个腺瘤上被执行，结果与病人的恶意的潜力，腺瘤的地点，宏观的外观和年龄的参数相比。结果：APC 蛋白质的完全的损失在 28 被发现的 A (24%) 腺瘤，当(76%) 90 是 APC 时积极。腺瘤的吝啬的尺寸是 13.5 +/- 14.2 公里(95% CI 10.5-16.5 ) 在 APC 积极，并且 13.8 +/- 在 APC 否定的腺瘤的 15.5 公里(95% CI 7.8-19.8 )(P = 0.364 ) 。统计分析没至于组织学的类型揭示 APC 积极、否定的腺瘤之间的差别(P = 0.327 ) 并且发育异常的等级(P = 0.494 ) 。我们发现甚至先进的腺瘤没与非先进的肿瘤在他们的 APC 地位不同(P = 0.414 ) 。最后，当时，没有差别被发现地点(P = 0.157 ) ，宏观的外观(P = 0.571 ) 并且病人的年龄(P = 0.438 ) 在两个 APC 积极、否定的腺瘤之间被分析并且比较。结论：大多数腺瘤表示了全身的 APC 蛋白质，建议那蛋白质表情不是为对 APC 基因变化的评价的一个可靠标记。APC 蛋白质的完全的损失没影响腺瘤的形态学，地点，或外观，它也不受病人的年龄影响。

与家庭 adenomatous polyposis coli 联系的 Hepatocellular 腺瘤

Hepatocellular adenoma (HCA) is a benign liver tumor that most frequently occurs in young women using oral contraceptives. We report a rare case of HCA in a 29 years old female with familial adenomatous polyposis (FAP). The first proband was her sister, who under-went a total colectomy and was genetically diagnosed as FAP. A tumor, 3.0 cm in diameter, was detected in the right lobe of the liver during a screening study for FAP. A colonoscopy and gastroendoscopy revealed numerous adenomatous polyps without carcinoma. The patient underwent a total colectomy and ileoanal anastomosis and hepatic posterior sectoriectomy. The pathological findings of the liver tumor were compatible with HCA. The resected specimen of the colon revealed multiple colonic adenomatous polyps. Examination of genetic alteration revealed a germ-line mutation of the adenomatous polyposis coli (APC) gene. Inactivation of the second APC allele was not found. Other genetic alterations in the hepatocyte nuclear factor 1 alpha and β-catenin gene, which are reported to be associated with HCA, were not detected. Although FAP is reported to be complicated with various neoplasias in extracolic organs, only six cases of HCA associated with FAP, including the present case, have been reported. Additional reports will establish the precise mechanisms of HCA development in FAP patients.

Aspirin-induced long-term tumor remission in hepatocellular carcinoma with adenomatous polyposis coli stop-gain mutation:A case report

BACKGROUND Targeted therapy based on pathway analysis of hepatitis B-related hepatocellular carcinoma(HCC)may be a promising remedy.CASE SUMMARY The present case involved an advanced hepatocellular carcinoma(HCC)patient who did not receive local regional therapy and was intolerant to sorafenib.Total RNA extracted from the patient’s tumor tissue was used to obtain the gene mutation profile.The c.3676A>T and c.4402A>T stop-gain mutations in adenomatous polyposis coli(APC)were the most prevalent(42.2%and 35.1%,respectively).MutationMapper analysis indicated that the functional domain of APC was lost in the two APC mutant genes.APC is a major suppressor of the Wnt signaling pathway.Thus,the Wnt pathway was exclusively activated due to APC dysfunction,as other elements of this pathway were not found to be mutated.Aspirin has been reported to suppress the Wnt pathway by inducingβ-catenin phosphorylation through the activation of glycogen synthase kinase 3 beta via cyclooxygenase-2 pathway inhibition.Therefore,aspirin was administered to the patient,which achieved four years of disease control.CONCLUSION Exclusive mutations of APC of all the Wnt pathway elements could be a therapeutic target in HCC,with aspirin as an effective treatment option.

Three Novel Mutations of APC Gene Found in a Chinese Family with Familial Adenomatous Polyposis

Objective:To identify the causative adenomatous polyposis coli(APC)gene defects associated with a pedigree of familial adenomatous polyposis(FAP).Methods:FAP was diagnosed based on clinical manifestations,family history,as well as endoscopic and pathological examinations.The blood samples of the FAP pedigree members,colonic polyp patients,and normal individuals were collected.Genomic DNA was then extracted from those samples.APC mutation analysis was conducted via direct polymerase chain reaction(PCR)sequencing.Results:Three synonymous mutations and a missense mutation were found:c.5034G>A(p.Glyl678Gly),c.5465T>A(p.Vall 822Asp),c.5880G>A(p.Prol960Pro),and c.5274T>G(p.Serl758Ser)・Among them,the homozygous mutation on APC gene c.5034G>A has been reported,while the other three mutations have not been reported in the Chinese Han population.Individuals with c.5465T>A(p.Vall822ASP)missense mutation eventually suffer from colon cancer and have poor prognosis.We found no mutation in patients with simple intestinal polyp and in normal individuals.In addition,there were homozygous and heterozygous mutations in different patients from the same family.Conclusion:Three new mutations of APC gene were firstly reported in Han population.The missense mutation of c.5465T>A(p.Vall 822Asp)may be the cause of carcinogenesis in this FAP pedigree with poor prognosis.

Clinicopathological features of familial adenomatous polyposis in Korean patients

AIM: To identify prognostic factors and to correlate APC mutations with clinical features, including extracolic manifestations. METHODS: One hundred thirty-five patients who underwent surgical procedures for familial adenomatous polyposis(FAP) were included. FAP was diagnosed when the number of adenomatous polyps was > 100. Data related to patient, extracoloic manifestations, cancer characteristics, operative procedure, follow up and surveillance were collected. APC mutation testing was performed in the 30 most recent patients. DNA was extracted from peripheral blood and polymerase chain reaction products using 31 primer pairs on APC gene were sequenced. A retrospective study was performed to investigate a causal relationship between prognosis and feature of patient.RESULTS: The mean age of the 51 patients with colorectal cancer(CRC) was older than that of those without CRC(30.5 vs 36.9, P = 0.002). Older individuals were more likely to have colon cancer at the time of FAP diagnosis [odds ratio, 4.75(95%CI: 1.71-13.89) and 5.91(1.76-22.12) for 40-49 years and age > 50 vs age < 30). The number of confirmed deaths was 13 and the median age at death was 40 years(range, 27 to 85 years). Ten of the deaths(76.9%) were from CRC. Another cause of two cases of death were desmoid tumors(15.4%). Development of cancer on remnant rectal or ileal mucosa after surgery was not observed. The APC mutation testing revealed 23 pathogenic mutations and one likely pathogenic mutation, among which were four novel mutations. The correlation between mutational status and clinical manifestations was investigated. Mutations that could prodict poor prognosis were at codon 1309 which located on mutation cluster region, codon 1465 and codon 1507.CONCLUSION: Identification of APC mutations should aid in the diagnosis and counseling of family members in terms of early diagnosis and management of FAP.

Attenuated adenomatous polyposis of the large bowel: Present and future

Attenuated adenomatous polyposis(AAP) is a poorly understood syndrome, that can be defined as the presence of 10-99 synchronous adenomas in the large bowel, and it is considered a phenotypic variant of familial adenomatous polyposis(FAP). This definition has the advantage of simplicity, but it may include sporadic multiple adenomas of the large bowel at an extreme, or FAP cases on the other side. AAP shows a milder phenotype than FAP, with an older age of onset of adenomas and cancer, and less frequent extracolonic manifestations. AAP may be diagnosed as a single case in a family or, less frequently, it may be present in other family members, and it shows distinct pattern of inheritance. In less than 50% of cases, it may be caused by adenomatous polyposis coli(APC) or MUTYH mutations, referred to as APC-associated polyposis, inherited as an autosomal dominant trait, or MUTYH-associated polyposis, which shows an autosomal recessive mechanism of inheritance, respectively. Surveillance should rely on colonoscopy at regular intervals, with removal of adenomas and careful histological examination. When removal of polyps is not possible or advanced lesions are observed, the surgical approach is mandatory, being subtotal colectomy with ileo-rectal anastomosis the treatment of choice. Studies on this syndrome are lacking, and controversies are still present on many issues, thus, other clinical and genetic studies are requested.

Rare combination of familial adenomatous polyposis and gallbladder polyps

Familial adenomatous polyposis is associated with a high incidence of malignancies in the upper gastrointestinal tract(particularly ampullary adenocarcinomas).However,few reports have described a correlation between familial adenomatous polyposis and gallbladder neoplasms.We present a case of a 60-year-old woman with familial adenomatous polyposis who presented with an elevated mass in the neck of the gallbladder(measuring 16 mm×8 mm in diameter)and multiple small cholecystic polyps.She had undergone a total colectomy for ascending colon cancer associated with familial adenomatous polyposis 22 years previously.The patient underwent laparoscopic cholecystectomyunder a preoperative diagnosis of multifocal gallbladder polyps.Pathologic examination of the resected gallbladder revealed more than 70 adenomatous lesions,a feature consistent with adenoma of the gallbladder.This case suggests a requirement for long-term surveillance of the biliary system in addition to the gastrointestinal tract in patients with familial adenomatous polyposis.

Presence of c.3956del C mutation in familial adenomatous polyposis patients from Brazil

AIM: To characterize APC gene mutations and correlate them with patient phenotypes in individuals diagnosed with familial adenomatous polyposis(FAP) in northern Brazil. METHODS: A total of 15 individuals diagnosed with FAP from 5 different families from the north of Brazil were analyzed in this study. In addition to patients with histopathological diagnosis of FAP,family members who had not developed the disease were also tested in order to identify mutations and for possible genetic counseling. All analyzed patients or their guardians signed a consent form approved by the Research Ethics Committee of the Jo?o de Barros Barreto University Hospital(Belem,Brazil). DNA extracted from the peripheral blood of a member of each of the affected families was subjected to direct sequencing. The proband of each family was sequenced to identify germline mutations using the Ion Torrent platform. To validate the detected mutations,Sanger sequencing was also performed. The samples from all patients were also tested for the identification of mutations by real-time quantitative polymerase chain reaction using the amplification refractory mutation system. RESULTS: Through interviews with relatives and a search of medical records,it was possible to construct genograms for three of the five families included in the study. All 15 patients from the five families with FAP exhibited mutations in the APC gene,and all mutations were detected in exon 15 of the APC gene. In addition to the patients with a histological diagnosis of FAP,family members without disease symptoms showed the mutation in the APC gene. In the present study,we detected two of the three most frequent germline mutations in the literature: the mutation at codon 1309 and the mutation at codon 1061. The presence of c.3956 del C mutation was found in all families from this study,and suggests that this mutation was introduced in the population of the State of Pará through ancestor immigration(i.e.,a de novo mutation that arose in one member belonging to this state from Brazil). CONCLUSION: Regardless of its origin,the c.3956 del C mutation is a strong candidate biomarker of this hereditary cancer syndrome in families of northern Brazil.

Cumulative incidence and risk factors for pouch adenomas associated with familial adenomatous polyposis following restorative proctocolectomy

BACKGROUND The emergence of restorative total proctocolectomy has significantly reduced the lifetime colorectal cancer risk associated with familial adenomatous polyposis(FAP).However,adenomas may develop in the ileal pouch over time and may even progress to carcinoma.We evaluated the cumulative incidence,time to development,and risk factors associated with ileal pouch adenoma.AIM To evaluate the cumulative incidence,time to development,and risk factors associated with pouch adenoma.METHODS In this retrospective,observational study conducted at a tertiary center,95 patients with FAP who underwent restorative proctocolectomy at our center between 1989 and 2018 were consecutively included.The mean follow-up period was 88 mo.RESULTS Pouch adenomas were found in 24(25.3%)patients,with a median time of 52 mo to their first formation.Tubular adenomas were detected in most patients(95.9%).There were no high-grade dysplasia or malignancies.Of the 24 patients with pouch adenomas,13 had all detected adenomas removed.Among the 13 patients who underwent complete adenoma removal,four(38.5%)developed recurrence.Among 11(45.8%)patients with numerous polyps within the pouch,seven(63.6%)exhibited progression of pouch adenoma.The cumulative risks of pouch adenoma development at 5,10,and 15 years after pouch surgery were 15.2%,29.6%,and 44.1%,respectively.Severe colorectal polyposis(with more than 1000 polyps)was a significant risk factor for pouch adenoma development(hazard ratio,2.49;95% confidence interval:1.04-5.96;P=0.041).CONCLUSION Pouch adenomas occur at a fairly high rate in association with FAP after restorative proctocolectomy,and a high colorectal polyp count is associated with pouch adenoma development.

Proton pump inhibitors and an emerging epidemic of gastric fundic gland polyposis

Fundic gland polyps are now commonly recognized during endoscopy. These polyps are benign, often multiple and usually detected in the gastric body and fundus. In the past, these polyps were sometimes associated with familial adenomatous polyposis. In recent years, it has become evident that increasing numbers of these polyps are being detected during endoscopic studies, particularly in patients treated with proton pump inhibitors for prolonged periods. In some, dysplastic changes in these polyps have also been reported. Recent studies have suggested that there may be no increase in risk of colon cancer with long-term proton pump inhibitor therapy. While temporarily reassuring, ongoing vigilance, particularly in those genetically predisposed to colon cancer, is still warranted.

应用组织芯片检测食管鳞状细胞癌中APC、β-catenin、E-cadherin与cyclin D1的表达及其意义

背景与目的:食管鳞状细胞癌(esophageal squamous cell carcinoma,ESCC)的发生是个多因素多阶段的演进过程。Wnt信号转导通路在肿瘤发生发展中起重要作用。本研究探讨4种Wnt通路上的蛋白在食管鳞癌发生中的作用及在早期诊断中的意义。方法:制作由199例食管鳞癌组织与其癌旁164例正常粘膜、34例基底细胞增生和30例不典型增生上皮组成的组织芯片,应用免疫组化方法检测APC、β-catenin、E-cadherin、cyclin D1的表达情况。结果:APC和E-cadherin在ESCC阳性率分别是69.6%、19.6%,均低于各自正常组(98.0%、96.3%,均为P<0.01),β-catenin和cyclinD1在ESCC的异常表达率分别是65.5%和70.9%,均高于各自正常组(1.2%,0.8%,均为P<0.01)。按正常粘膜→基底细胞增生→不典型增生→ESCC的顺序,APC低表达发生在ESCC,β-catenin和E-cadherin表达异常始于不典型增生,cyclin D1过表达始于基底细胞增生。随着ESCC分化程度由高到低的改变,APC、E-cadherin和cyclin D1阳性率逐渐减少,β-catenin逐渐增加。β-catenin的表达与APC无相关(r=-0.10,P>0.05),与E-cadherin呈负相关(r=-0.31,P<0.01),与cyclin D1呈正相关(r=0.49,P<0.01)。结论:APC、E-cadherin、β-catenin和cyclin D1可能在ESCC发生过程中起重要作用。β-catenin、E-cadherin和cyclin D1的表达检测有助于ESCC的早期诊断。

抑癌基因APC启动子甲基化检测及其在肺癌诊断中的应用

目的 建立抑癌基因APC启动子部位甲基化的检测方法 ,并对肺癌临床样品进行初步检测研究。方法 :对肺癌组织提取的DNA及转甲基后的脐带血DNA进行化学修饰 ,以甲基化特异性引物进行基因扩增 (methylationspecificPCR ,MSP)和甲基化序列分析 (methylationsequencing ,MS)。结果 :经转甲基的人脐带血DNA样品MSP检测为阳性 ,其序列与预期相符 ,未经转甲基样品为阴性。 17例肺癌患者的肿瘤及其正常肺组织APC甲基化检测阳性率分别为 4 7% (8/ 17)和 18% (3/ 17) ,1例肺部良性肿瘤及其正常肺组织的检测结果均为阴性 ;对MSP检测为阴性的 9例肺癌患者肿瘤及其正常肺组织进行MS检测分析 ,有 4例APC启动子部位存在CpG甲基化。结论 :利用MSP和MS两种甲基化检测分析手段 ,对 17例临床确诊肺癌组织的检测总阳性率可达 71% (12 / 17)。MSP操作简便 ,价格低廉 ,可适合于大规模肿瘤患者样本的筛查 ;而对于MSP检测为阴性的临床样品 ,可以利用MS进行进一步的确认 ,为临床肺癌诊断提供更准确的信息。

APC不同功能区域对结肠癌细胞株HT-29中β-连环蛋白表达的影响

目的:探讨含有APC蛋白不同功能区域的pEGFP-N3-APC重组质粒对结肠癌细胞株HT-29中β-连环蛋白表达的影响。方法:脂质体介导重组质粒pEGFP-N3-APC1～5转染HT-29,采用绿色荧光及RT-PCR验证重组质粒在细胞中的表达。以Western免疫印迹检测转染后HT-29细胞中β-连环蛋白的表达,以SPSS13.0软件分析电泳条带的灰度值。结果:重组质粒转染HT-29细胞后,绿色荧光及RT-PCR结果显示5个APC蛋白不同功能区域多肽可在细胞中表达。Western免疫印迹结果显示,重组质粒pEGFP-N3-APC1,pEGFP-N3-APC2和pEGFP-N3-APC3对β-连环蛋白表达无影响,而pEGFP-N3-APC4和pEGFP-N3-APC5均可降低结肠癌细胞株HT-29中β-连环蛋白的表达水平,其中以pEGFP-N3-APC5的抑制程度最强。结论:含有APC蛋白中15氨基重复序列+SAMP重复序列的APC5基因片段既可有效降低β-连环蛋白的表达,同时又是相对长度较短的可用于基因治疗的最优片段。

大肠癌APC、β-catenin、E-cadherin和c-myc的表达及意义

目的探讨腺瘤性息肉蛋白(APC)、β-catenin、E-cadherin和c-myc在大肠癌发生、发展中的作用。方法采用免疫组化法检测正常大肠黏膜、大肠腺瘤、大肠腺瘤恶变及大肠癌组织中上述4种蛋白的表达情况。结果大肠癌和大肠腺瘤恶变APC阳性率显著低于大肠腺瘤和正常大肠黏膜(P<0.01)。大肠癌、大肠腺瘤恶变和大肠腺瘤β-catenin胞质/胞核异位表达率、c-myc阳性率显著高于正常大肠黏膜(P<0.01),大肠癌的β-catenin异位表达率显著高于大肠腺瘤(P<0.01)。大肠癌中β-catenin、E-cadherin膜表达缺失率显著高于大肠腺瘤和正常大肠黏膜(P<0.01)。大肠癌中β-catenin异位表达与c-myc阳性表达、E-cadherin阳性表达呈正相关,与APC阳性表达呈负相关。结论APC失表达和(或)β-catenin异位表达、c-myc过表达与大肠癌的发生相关,β-catenin、E-cadherin膜表达缺失与大肠癌的侵袭、转移有关。

家族性腺瘤性息肉病患者APC基因胚系突变的初步研究

目的:探讨国人家族性腺瘤性息肉病(FAP)患者APC基因胚系突变的特点。方法:对我院2004年3月至2005年3月收治的6例FAP患者运用PCR-变性高效液相色谱技术检测APC基因,对可疑突变者进行测序。结果:变性高效液相色谱检测共发现3个可疑突变片段,经DNA测序证实3个片段均存在突变。其中,15号外显子2例,14号内含子1例。结论:国人FAP患者相同基因型APC基因突变可有不同表现型。

应用蛋白截短技术检测APC基因胚系突变

建立蛋白截短检测技术,分析家族性腺瘤样息肉病(FAP)发病相关基因APC基因的胚系突变,研究基因突变型与FAP疾病表型的关系。经临床诊断的22例FAP患者及43例散发性大肠癌患者,分别取外周静脉血和正常结肠粘膜组织,常规提取基因组DNA。应用蛋白截短检测技术,分段分析APC基因巨大的第15外显子,对检出截短蛋白的样本进行测序,以确定突变位点及突变性质。22例FAP患者中,5例患者存在APC基因第15外显子的胚系突变,均为碱基缺失造成的移码突变,导致截短蛋白的产生;43例散发性大肠癌患者中未检测到APC基因第15外显子的胚系突变。蛋白截短检测技术是一种高效的基因突变分析技术,适用于大片段基因(如APC基因第15外显子)截短型突变的检测,可作为FAP症状出现前的常规基因诊断技术的一项有效补充。

乳腺癌APC基因甲基化状况及其蛋白表达

背景与目的:结肠腺瘤性息肉病基因(adenomatous polyposis coli,APC)蛋白表达产物是Wnt信号转导途径重要组成部分,该基因失活使β-catenin蛋白降解障碍,从而使Tcf/Lef激活,引起基因异常转录,最终产生癌变。启动子区甲基化是导致抑癌基因转录失活的重要机制。本研究探讨乳腺癌APC基因启动子1A区甲基化状态与其蛋白表达的关系,并分析APC基因异常甲基化与乳腺癌临床病理特征的关系。方法:应用甲基化特异性PCR和免疫组织化学方法检测76例乳腺癌及相应癌旁乳腺组织中APC基因启动子1A区甲基化状态以及蛋白表达。结果:癌旁乳腺组织中均未发现APC基因启动子1A区甲基化,乳腺癌组织中APC基因启动子1A区甲基化率为36.8%。癌旁乳腺组织中APC蛋白阳性率为100%,乳腺癌中APC蛋白阳性率为52.4%。乳腺癌组织中APC基因甲基化与APC蛋白表达呈负相关(r=-0.351,P<0.05),与TNM分期呈正相关(r=0.335,P<0.05)。结论:乳腺癌发展过程中APC基因启动子1A区出现异常甲基化,是导致该蛋白表达缺失的主要原因,是导致该基因失活的重要机制之一。

子宫内膜样腺癌APC基因表达和甲基化的初步研究

背景与目的:子宫内膜癌是女性生殖系统常见的恶性肿瘤之一。在我国,近年来其发病率亦显著上升。APC基因是一种抑癌基因,在很多组织中都有表达,其表达与卵巢癌有一定的关系。本实验探讨APC基因的甲基化和表达与子宫内膜样腺癌的发生发展的关系。方法:运用甲基化特异性PCR、RT-PCR、免疫组化方法检测了30例正常的增生期子宫内膜组织、30例不典型增生的子宫内膜组织、60例子宫内膜样腺癌组织中APC基因的甲基化情况以及mRNA和蛋白的表达情况。结果:子宫内膜样腺癌组织中APC基因的甲基化率(65.0%)、mRNA表达率(33.3%)及APC蛋白表达率(30.0%)与不典型增生子宫内膜组织(33.3%、63.3%、50.0%)及正常子宫内膜(23.3%、73.3%、66.7%)相比,差异均具有显著性(P<0.05);而不典型增生子宫内膜组织和正常子宫内膜组织中,APC的甲基化率、mRNA表达率及APC蛋白表达率差异无统计学意义(P>0.05)。在这3种组织中,APC基因的甲基化和mRNA的失表达呈正相关关系。结论:APC的甲基化和表达与子宫内膜样腺癌的发生发展相关。

散发性结直肠癌组织APC突变的研究

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