Intrathoracic sporadic desmoid tumor with the beta-catenin gene mutation in exon 3 and activated cyclin D1

We report a case of intrathoracic desmoid tumor without familial adenomatous polyposis and demonstrate beta-catenin mutation of exon 3. A 15-year-old male presented with a desmoid tumor after having sustained an assault. In an examination for a mutation of the beta-catenin gene, an activating mutation from ACC (Thr) to GCC (Ala) at codon 41 was found. Immunohistochemical staining showed that accumulated beta-catenin protein was predominantly localized in the nuclei of desmoid cells, and cyclin D1 protein was also overexpressed. These findings might suggest that an activating mutation of the beta-catenin gene affected regulation of the cyclin D1 gene, resulting in the generation of intrathoracic sporadic desmoid tumor, which arose at the site of posttraumatic injury.     

散发性嗜铬细胞瘤患者SDHB基因突变筛查

应用PCR扩增102例嗜铬细胞瘤患者抑癌基因SDHB并直接测序,结果显示有3例患者存在基因突变.分别为2号外显子CGA→TGA(R46X)、3号外显子CGA→TGA(Rgox)和7号外显子CGC→CAC(R242H),推测抑癌基因SDHB在散发性嗜铬细胞瘤患者中的突变率约为3%.     

Mutations in the VHL gene in sporadic apparently congenital polycythemia

The congenital polycythemic disorders with elevated erythropoietin (Epo) have been until recently an enigma, and abnormality in the hypoxia-sensing pathway has been hypothesized as a possible mechanism. The tumor suppressor von Hippel-Lindau (VHL) participates in the hypoxia-sensing pathway, as it binds to the proline-hydroxylated form of the hypoxia-inducible factor 1alpha (HIF-1alpha) and mediates its ubiquitination and proteosomal degradation. The loss of VHL function may result in the accumulation of HIF-1alpha and overproduction of HIF-1 downstream target genes including Epo. VHL syndrome is an autosomal dominant disorder predisposing to the development of tumors, due to inherited mutations in the VHL gene. Some rare patients with VHL syndrome have polycythemia, which has been attributed to Epo production by a tumor. It was recently found that homozygosity for the VHL Arg200Trp mutation is the cause of Chuvash polycythemia, an autosomal recessive polycythemic disorder characterized by elevated serum Epo and hypersensitivity of erythroid cells to Epo. We evaluated the role of VHL in 8 children with a history of polycythemia and an elevated serum Epo level and found 3 different germline VHL mutations in 4 of them. One child was homozygous for the Arg200Trp VHL mutation, and another compound heterozygous for the Arg200Trp and the Val130Leu mutations. Two children (siblings) were heterozygous for an Asp126Tyr mutation, one of them fulfilling some criteria of VHL syndrome. We propose that mutations of the VHL gene represent an important cause of pediatric sporadic polycythemias with an inappropriately high serum Epo concentration.     

Prednisolone therapy for intra-abdominal desmoid tumors in a patient with familial adenomatous polyposis

The management of intra-abdominal desmoid tumors in patients with familial adenomatous polyposis (FAP) is very difficult. Non-steroidal anti-inflammatory drugs (NSAIDs), anti-estrogenic agents, and steroids are most commonly used, because surgical removal of these tumors may result in severe morbidity, with local recurrence being common. We report a patient with FAP and intra-abdominal desmoid tumors that regressed markedly after prednisolone therapy. The patient, a 38-year-old woman, had undergone total colectomy and ileorectal anastomosis with a diagnosis of FAP with colon cancer. Approximately 17 months after the surgery, she noticed an elastic firm lump in the abdominal wall. She also experienced lower abdominal distension. Computed tomography (CT) of the lower abdomen showed an invasive heterogenous low-density mass occupying the intra-abdominal space. She was treated with sulindac, NSAID, at 300 mg/day, the diagnosis being intra-abdominal desmoid tumors. She exhibited an intestinal obstruction about 9 months after the initiation of sulindac therapy. We changed the treatment and began prednisolone (initial dose, 40 mg/day). This treatment was continued for two years; subsequently the lesions regressed markedly. She is currently well, more than 3 years after the withdrawal of prednisolone.     

Characterization of APC exon 15 germ-line mutation in FAP family with severe phenotype showing extracolonic symptoms

The adenomatous polyposis coli (APC) gene plays a crucial role in colorectal carcinogenesis. Germ-line mutations of APC gene give rise to familial adenomatous polyposis coli (FAP) - autosomal dominant syndrome manifesting hundreds to thousands of colorectal polyps, if untreated with malignant progression. We have used the techniques of heteroduplex analysis (HDA), protein truncation test (PTT), single strand conformation polymorphism (SSCP) and DNA sequencing for the identification and detailed positional analysis of mutations in IFAP family with the expressive phenotype characterized by polyposis and extracolonic lesions. Detailed analysis revealed a 5bp deletion in a mutation cluster region (MCR) in exon 15 of APC gene in codon 1308. Two screened members of the FAP family exhibited this novel mutation.     

Mutations of the APC gene in human sporadic colorectal cancers

BACKGROUND: Mutations of the APC gene are reported to occur frequently in sporadic colorectal adenomas and adenocarcinomas. We studied APC gene mutations in cases of human sporadic colorectal cancer in order to evaluate their correlation with pathologic characteristics and clinical prognosis. METHODS: Most of the mutations of the APC gene (95%) are nonsense or frame shift mutations, encoding for truncated APC proteins. For this reason, mutation detection of the APC gene was performed using the in vitro synthesized protein (IVSP) assay, analysing the region between nucleotide 2058 and nucleotide 5079 of the gene, containing the mutation cluster region. RESULTS: Out of 58 cases of colorectal cancer, 29 presented a mutated form of APC (mutation frequency 50%). We did not find a statistically significant correlation between APC gene mutation and age, sex, localization of the primary tumour, grading, Crohn-like lymphoid reaction or presence of residual adenoma. Tumours with low invasivity (Dukes' stages A and B) were less frequently mutated (12/27, 44.5%) than tumours of Dukes' stage C (15 out of 21, 71.4%), which developed macroscopically secondary metastasis with variable latency after surgery. Highly invasive tumours with synchronous metastases (Dukes' stage D) had, instead, a low frequency of APC mutations (20%, 2/10) (P = 0.02, compared with Dukes' stages A, B and C). Conclusions: These data suggest that more aggressive Dukes' stage D tumours develop metastasis by means of an unknown mechanism, independent of APC mutation.     

Functional consequences of a SDHB gene mutation in an apparently sporadic pheochromocytoma

Three genes encoding for mitochondrial complex II proteins are linked to hereditary paraganglioma. We have recently shown that an inactivation of the SDHD gene is associated with a complete loss of mitochondrial complex II activity and a stimulation of the angiogenic pathway (Gimenez-Roqueplo, A. P., J. Favier, P. Rustin, J. J. Mourad, P. F. Plouin, P. Corvol, A. R?tig, and X. Jeunemaitre, 2001, Am J Hum Genet 69:1186-1197). Here, we relate the case of a malignant sporadic pheochromocytoma induced by a germline missense mutation of the SDHB gene. Within the tumor, a loss of heterozygosity at chromosome 1pter led to a null SDHB allele and to a complete loss of complex II enzymatic activity. In situ hybridization and immunohistochemistry experiments showed a high expression of hypoxic-angiogenic responsive genes, similar to that previously observed in inherited-SDHD tumors. This observation highlights the role of the complex II mitochondrial genes in the oxygen-sensing pathway and in the regulation of angiogenesis of neural crest-derived tumors.     

Mutation analysis of APC gene in gastric cancer with microsatellite instability

AIM：To evaluate the role of APCmutation in gastric carcinogenesis and to correlate APC mutation with microsatellite instability(MSI)in gastiric carcinomas.METHODS:APC mutation was measured with multiplexPCR,denaturing gradient gel electrophoresis and DNAsequencing;and MSIwas analyzed by PCR-based methods.RESULTS:Sixty-eight cases of sporadis gastric carcinoma were studied for APCmutation at exon15and MSI,APC mutaions were detected in15(22.1%)gastric cancers,Frequence of APCmutation(33.3%)in in testinal type of gastric ancer was significantly higher than that in diffuse type(13.1%,P<0.05).On the contrary.on association was observed dbtween APC mutation and tumor size,differentiation,depth of invasion,metastasis or clinical stages.Using five microsatellite markers.MSIin at least one locus was detected in 17of68(25%)of the tumors analyzed,APC mutations were all detected in MSI-L(only one locus,n=9)orMSS(tumor lacking MSI or stable,n=51),but no mutation was found in MSI-H(≥2loci,n=8).CONCLUSION:APC mutation is involved in carcinogenesis of intestial type of gastric cancer and is independent of MSI phenotype but related to the LOH pathway in gastri cancer.     

散发性扩张型心肌病相关ISL1基因突变分析

目的:分析散发性扩张型心肌病(DCM)相关ISL1基因突变谱。方法:收集226例散发性DCM患者和230名相匹配的健康人的血标本,抽提DNA。通过聚合酶链反应-测序分析ISL1基因的编码外显子及侧翼内含子。对所发现的ISL1基因突变,应用ClustalW2软件评估突变氨基酸在进化上的保守性,应用在线程序MutationTaster、PolyPhen-2和PROVEAN预测突变的致病性,应用双荧光素酶报告基因分析系统评估突变的功能效应。结果:在1例散发性DCM患者的ISL1基因中检测出1个新的杂合错义突变(c.706G>T即p.Asp236Tyr),该突变不存在于对照组。跨物种ISL1蛋白序列比对分析表明该被改变的氨基酸在进化上完全保守,致病性预测显示该基因突变具有致病性,生化分析表明突变体对靶基因的转录激活功能显著降低。结论:发现1个ISL1基因功能缺失性新突变,可能导致DCM,对DCM的早期个体化防治具有潜在的临床意义。     

Endothelium-dependent vasodilation is impaired in apparently healthy subjects with a family history of myocardial infarction

OBJECTIVES: To investigate whether endothelial-dependent vasodilation is altered in healthy subjects with a family history of myocardial infarction. SETTING: Tertiary University Hospital SUBJECTS AND DESIGN: Fifty apparently healthy subjects selected from the general population were subjected to an evaluation of endothelial-dependent vasodilation (EDV) and endothelial-independent vasodilation (EIDV) by means of local infusion of methacholine (MCh, 2 and 4 microg/min) and sodium nitroprusside (SNP, 5 and 10 microg/min) with measurements of forearm blood flow with venous occlusion plethysmography. The occurrence of plaque and the intima-media thickness of the carotid arteries were determined by ultrasonography. RESULTS: Subjects reporting at least one parent suffering from myocardial infarction (n = 11) showed a significantly lower EDV than subjects without such a family history (21 +/- 3.7 vs. 26 +/- 6.7 ml/min/100 ml tissue at MCh 4 microg/min, P<0.05). EIDV was not significantly different between the groups (21 +/- 6.8 vs. 18 +/- 5.4 ml/min/100 ml tissue at SNP 10 microg/min). Age, sex distribution, body mass index, waist to hip ratio, blood pressure, lipids, fasting blood glucose, smoking habits and status of the carotid arteries were not significantly different between the groups. CONCLUSION: A family history of myocardial infarction was found to be associated with an impaired endothelial-dependent vasodilation in the forearm of apparently healthy subjects. The risk factor profile was not different from the control group, suggesting that genetic factors are responsible for the impaired endothelial-dependent vasodilation.     

家族性高胆固醇血症低密度脂蛋白受体基因突变分析

目的:检测1例家族性高胆固醇血症(FH)先证者及其4代家系成员低密度脂蛋白受体(LDL-R)基因突变,探讨该家族FH可能发病分子机制.方法:收集先证者及其家系成员临床资料和基因组DNA,以基因组DNA为模板,用PCR方法扩增LDL-R基因的启动子和全部18个外显子,PCR产物进行限制性内切酶技术结合DNA测序,核苷酸序列分析结果与Gen Bank比对寻找突变;采用PCR-DNA测序技术检测apoB100基因R3500Q、R3531C和R3500W位点以及枯草溶菌素转化酶9(PCSK9)基因,以排除家族性apoB100缺陷症和PCSK9基因突变.结果:先证者及其部分家系成员第6号外显子发生Cys276X杂合无义突变,为半胱氨酸改变为提前终止密码子,使终止密码子在第276位提前出现,为致病性突变,国内尚无报道;另外,第15号外显子发生Arg744Arg同义突变.其母未发现上述突变,未检测出患者及其家系apoB100基因R3500Q、R3531C和R3500W突变以及枯草溶菌素转化酶9基因突变.结论:此患者及家系LDL-R基因存在Cys276X无义突变,可能是FH的致病突变,该突变是我国FH患者LDLR基因的一种新突变类型.     

Mutation analysis of PTEN/MMAC 1 in sporadic thyroid tumors

Recently, a putative tumor suppressor gene, PTEN/MMAC1, has been identified at chromosome 10q23.3. This gene encodes a 403 amino acid dual specificity phosphatase containing a region of homology to tensin and auxillin. Somatic mutations of the PTEN/MMAC1 gene have been found in a number of cancer cell lines and primary cancers. Cowden disease, an autosomal dominant harmartoma syndrome associated with thyroid and breast tumors, has been found to be associated with mutations of PTEN/MMAC1 gene. To evaluate the role of the PTEN/MMAC1 gene in sporadic thyroid tumors, we studied 17 sporadic thyroid tumors, of which 12 were papillary thyroid carcinomas, 1 was follicular thyroid carcinoma, 1 was medullary thyroid carcinoma and 3 were thyroid adenomas. Direct sequencing of PCR-amplified products was performed for all nine exons of PTEN/MMAC1. No mutations of PTEN/MMAC1 gene were observed in any of the sporadic thyroid tumors. Our results indicate that the PTEN/MMAC1 gene may not play a major role in sporadic thyroid tumors.     

A RET mutation with decreased penetrance in the family of a patient with a "sporadic" pheochromocytoma

We present the case of a 38-yr-old man with a sporadic, multifocal pheochromocytoma and paraganglioma who was discovered to carry a Y791F germline mutation in exon 13 of the RET proto-oncogene. This mutation was found in his 65-yr-old mother and his 86-yr-old maternal grandmother. Neither of them had either biochemical evidence of pheochromocytoma or medullary thyroid carcinoma. The patient had a pro-phylactic thyroidectomy, which revealed mild C-cell hyperplasia. This case brings to discussion several issues: (1) the benefit of screening patients with apparently sporadic pheochromocytomas for genetic mutations; (2) the management of patients and families with "lower-risk" RET mutations; and (3) the possibility that lower-penetrance RET mutations may contribute to the list of causes of familial pheochromocytomas.     

Multiple desmoid tumors in a patient with familial adenomatous polyposis caused by the novel W421X mutation

Familial adenomatous polyposis (FAP) is a rare syndrome characterized by the presence of hundreds to thousands of colorectal adenomas and is responsible for less than 1% of all colorectal cancers. The syndrome is also characterized by extra-colorectal features including amongst others upper gastrointestinal tract polyps and desmoid tumors. The syndrome is inherited by an autosomal dominant gene, the adenomatous polyposis coli (APC) gene. We present the physical history, clinical presentation, diagnosis and treatment of a patient with a novel germline APC mutation, the W421X mutation, which resulted in FAP presenting with about a hundred colorectal polyps, gastric hyperplastic polyps and multiple aggressive intra-abdominal and extra-abdominal desmoid tumors.     

大肠癌APC基因15外显子突变分析

目的　探讨APC基因突变在大肠癌发生中的作用及与临床病理参数和微卫星不稳 (MSl)的关系。方法　采用多重PCR、DGGE电泳和DNA测序技术检测 76例大肠癌APC基因 15外显子突变 ;采用PCR为基础的方法检测MSI。结果　 76例大肠癌中检出APC基因 15外显子突变 2 9例 ,突变率为 3 8 2 % ;APC基因突变多见于左侧大肠癌 ,但与肿瘤大小、分化程度、浸润深度和临床病理分期无显著相关。高频率微卫星不稳 (MSI H)大肠癌APC基因突变率显著低于低频率微卫星不稳 (MSI L)和微卫星稳定(MSS)大肠癌 (P <0 0 5～ 0 0 1)。结论　APC基因可能是散发型大肠癌的易感基因 ,APC基因突变在大肠癌的发生中可能参与了染色体不稳途径     

肝肿瘤家族性腺瘤息肉病抑癌基因外显子11的突变研究

目的 检测APC（家庭性腺瘤息肉病基因）抑癌基因在小儿肝脏肿瘤（hepatic turmors,HT）中的突变情况,并探讨APC抑癌基因的杂合性缺失及变化与HT生物学行为的关系。方法 采用聚合酶链反应-单链构象多态性（PCR-SSCP）、聚合酶链反应-限制性片段长度多态性（PCR-RFLP）方法,对HT患儿共36例及距肿瘤约10cm以外肝组织30例对照的APC抑癌基因的突变,进行了研究。结果 在肝母细胞瘤（hepatoblastoma,HB）患儿组中突变率为61.54%（8/13）;神经母细胞瘤（neuroblastoma,NB）患儿组为68.75%（11/16）;横纹肌肉瘤（rhabdomyosarcoma,RS）患儿组为57.14%（4/7）。实验结果表明,APC抑癌基因在HT中均有较高突变频率,三组比较差异无显著性,而正常组织无突变。结论 APC在HT中存在突变;它的突变至少参与了大部分HT的发生发展过程,可能涉及广谱人类肿瘤的发生;它的异常可能是恶性肿瘤发生较早的事件。