Immunohistochemical analysis of phospho-BAD protein and mutational analysis of BAD gene in gastric carcinomas

Mounting evidence indicates that deregulation of apoptosis contributes to the development of human cancers. BAD, a proapoptotic Bcl-2 family protein, regulates the intrinsic apoptosis pathway. The aim of this study was to explore whether alterations of phospho-BAD (p-BAD) protein that antagonizes apoptosis function of BAD and mutation of BAD gene are characteristics of human gastric cancers. We analyzed expression of p-BAD in 60 gastric adenocarcinomas by immunohistochemistry. Also, we analyzed BAD gene for detection of somatic mutations by single-strand conformation polymorphism (SSCP) assay. p-BAD expression was detected well in normal gastric mucosal epithelial cells, whereas it was detected in only 51% (31 of the 60) of the cancers. There was no somatic mutation of BAD gene in the 60 gastric cancer samples. The decreased expression of p-BAD in malignant gastric epithelial cells compared to normal mucosal epithelial cells suggested that loss of p-BAD expression may play a role in gastric tumorigenesis. The data also suggest that BAD mutation may not be a direct target of inactivation in gastric tumorigenesis.     

Genetic variants in the Hedgehog signaling pathway genes are associated with gastric cancer risk in a Chinese Han population

The Hedgehog signaling pathway participates in the occurrence and progression of cancers including gastric cancer.We conducted this study to evaluate whether genetic variants in the Hedgehog signaling pathway genes would affect gastric cancer risk.Multi-marker Analysis of GenoMic Annotation(MAGMA)was used to investigate the aggregated genetic effects of single nucleotide polymorphisms(SNPs)assigned to candidate genes.The relationship between SNPs and gastric cancer risk was estimated by multivariate logistic regression analyses.Gene expression was calculated using databases obtained from The Cancer Genome Atlas(TCGA)and The Gene Expression Omnibus(GEO).Kaplan‐Meier plotter was used to evaluate the association between gene expression with gastric cancer survival.Tumor Immune Estimation Resource 2.0(TIMER 2.0)was applied to determine the correlation between selected gene expression and the immune cell infiltration degree.We identified that the G allele of rs2990912 in KIF27 was associated with higher gastric cancer risk,especially in the young and male subgroups.The expression of KIF27 in gastric cancer tissues was higher than that in normal tissues,leading to poor survival in gastric cancer patients.Besides,KIF27 expression was related to immune cell infiltration and positively correlated with PD-L1 expression.Our findings highlight the key role of genetic variation in the Hedgehog signaling pathway genes in gastric cancer susceptibility,which may provide important insights into the diagnosis,prognosis,and treatment of gastric cancer.     

Immunohistochemical and mutational analysis of FLASH in gastric carcinomas

FLASH was initially identified as a pro-apoptotic protein that transmits an apoptosis signal during death receptor-induced apoptosis. Additionally, diverse biologic roles of FLASH, including TNF-induced NF-kappaB activation, cell-cycle progression and cell division, have been identified. Although such functions are important in cancer pathogenesis, little is known about the alterations of FLASH gene and FLASH protein expression in human cancers. In this study, we analyzed the expression of FLASH protein in 60 gastric adenocarcinomas by immunohistochemistry. We furthermore analyzed mutation of FLASH in exon 8, where two polyadenine tracts ((A)8 and (A)9) are present, by single-strand conformation polymorphism (SSCP) assay in 184 gastric adenocarcinomas. By immunohistochemistry, FLASH protein expression in cancer cells was detected positively in 42 gastric carcinoma tissues (70%), whereas its expression in epithelial cells of normal gastric mucosa was shown as no or very weak intensity. Mutational analysis detected one FLASH mutation in the gastric carcinomas (0.5%). The increased expression of FLASH in the malignant gastric epithelial cells compared to the normal mucosal epithelial cells suggests that FLASH expression may play a role in gastric tumorigenesis. Also, the data suggest that somatic mutation of FLASH is a rare event in gastric carcinomas.     

Familial adenomatous polyposis associated with multiple adrenal adenomas in a patient with a rare 3' APC mutation

Familial adenomatous polyposis (FAP) is characterised by hundreds of colorectal adenomas. Endocrine neoplasms have occasionally been reported, as have gastric polyps, which are usually hamartomatous in the fundus of the stomach and adenomatous in the antrum. A 57 year old man with colorectal, gastric, and periampullary adenomatous polyposis, in association with three bilateral adrenocortical adenomas, is presented. Mutation screening showed a 5960delA germline mutation in the adenomatous polyposis coli (APC) gene predicted to lead to a premature stop codon. This mutation was found in three of the four children of the patient. Western blot analysis of a lymphoblastoid cell line derived from the patient failed to detect any truncated APC polypeptide. This rare 3' mutation is responsible for an unusually complex and late onset phenotype of FAP.


Keywords: familial adenomatous polyposis; APC mutation; adrenal adenoma     

The mutational burdens and evolutionary ages of early gastric cancers are comparable to those of advanced gastric cancers

Early gastric cancers (EGCs) precede advanced gastric cancers (AGCs), with a favourable prognosis compared to AGC. To understand the progression mechanism of EGC to AGC, it is required to disclose EGC and AGC genomes in mutational and evolutionary perspectives. We performed whole‐exome sequencing and copy number profiling of nine microsatellite (MS)‐unstable (MSI‐H) (five EGCs and four AGCs) and eight MS‐stable (MSS) gastric cancers (four EGCs and four AGCs). In the cancers, we observed well‐known driver mutations (TP53, APC, PIK3CA, ARID1A, and KRAS) that were enriched in cancer‐related pathways, including chromatin remodelling and tyrosine kinase activity. The MSI‐H genomes harboured ten times more mutations, but were largely depleted of copy number alterations (CNAs) compared to the MSS cancers. Interestingly, EGC genomes showed a comparable level of mutations to AGC in terms of the number, sequence composition, and functional consequences (potential driver mutations and affected pathways) of mutations. Furthermore, the CNAs between EGC and AGC genomes were not significantly different in either MSI‐H and MSS. Evolutionary analyses using somatic mutations and MSI as molecular clocks further identified that EGC genomes were as old as AGC genomes in both MSS and MSI‐H cancers. Our results suggest that the genetic makeup for gastric cancer may already be achieved in EGC genomes and that the time required for transition to AGC may be relatively short. Also, the data suggest a possibility that the mutational profiles obtained from early biopsies may be useful in the clinical settings for the molecular diagnosis and therapeutics of gastric cancer patients. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

APC promoter 1B deletion in seven American families with familial adenomatous polyposis

Familial adenomatous polyposis (FAP) is a colorectal cancer predisposition syndrome caused by mutations in the adenomatous polyposis coli (APC) gene. Clinical genetic testing fails to identify disease causing mutations in up to 20% of clinically apparent FAP cases. Following the inclusion of multiplex ligation‐dependent probe amplification (MLPA) probes specific for APC promoter 1B, seven probands were identified with a deletion of promoter 1B. Using haplotype analysis spanning the APC locus, the seven families appear to be identical by descent from a common founder. The clinical phenotype of 19 mutation carriers is classical FAP with colectomy at an average age of 24. The majority of cases had a large number of duodenal and gastric polyps. Measurements of allele‐specific expression of APC mRNA using TaqMan assay confirmed that relative expression in the allele containing the promoter 1B deletion was reduced 42–98%, depending on tissue type. This study confirms the importance of APC promoter deletions as a cause of FAP and identifies a founder mutation in FAP patients from the United States.     

Loss-of-function and missense variants in NSD2 cause decreased methylation activity and are associated with a distinct developmental phenotype

PurposeDespite a few recent reports of patients harboring truncating variants in NSD2, a gene considered critical for the Wolf–Hirschhorn syndrome (WHS) phenotype, the clinical spectrum associated with NSD2 pathogenic variants remains poorly understood.MethodsWe collected a comprehensive series of 18 unpublished patients carrying heterozygous missense, elongating, or truncating NSD2 variants; compared their clinical data to the typical WHS phenotype after pooling them with ten previously described patients; and assessed the underlying molecular mechanism by structural modeling and measuring methylation activity in vitro.ResultsThe core NSD2-associated phenotype includes mostly mild developmental delay, prenatal-onset growth retardation, low body mass index, and characteristic facial features distinct from WHS. Patients carrying missense variants were significantly taller and had more frequent behavioral/psychological issues compared with those harboring truncating variants. Structural in silico modeling suggested interference with NSD2’s folding and function for all missense variants in known structures. In vitro testing showed reduced methylation activity and failure to reconstitute H3K36me2 in NSD2 knockout cells for most missense variants.ConclusionNSD2 loss-of-function variants lead to a distinct, rather mild phenotype partially overlapping with WHS. To avoid confusion for patients, NSD2 deficiency may be named Rauch–Steindl syndrome after the delineators of this phenotype.     

Tumor-associated proteases and inhibitors in gastric cancer: analysis of prognostic impact and individual risk protease patterns

Expression of proteolytic parameters of the urokinase-type plasminogen activator (uPA) system [uPA receptor (uPA-R), plasminogen activator inhibitor (PAI)-1] has been proven to be an independent prognostic parameter in cancer. However, it has not been considered that the uPA system is interacting with several other protease/inhibitor systems, neither has a comparable prognostic role of these factors been investigated. Moreover, studies evaluating specific protease patterns indicating high individual risk are missing completely. Therefore, in a consecutive prospective series of 203 gastric cancer patients, the expression of activators (plasminogen, tPA, MMP-2, cathepsin D, antithrombin 3) and inhibitors (a-2-antiplasmin, a-2-macroglobulin, a-1-antitrypsin, a-1-antichymotrypsin) of proteolysis was studied immunohistochemically in the tumor epithelium semiquantitatively (score 0-3) in addition to the uPA system. Kaplan-Meier analysis (median time of follow-up 31 months) revealed a significant association of cathepsin D (P = 0.0042), a-2-macroglobulin (P = 0.0281) and antitrypsin (P = 0.0372) with disease-free survival and of cathepsin D (P = 0.0018), antitrypsin (P = 0.0112) and antichymotrypsin (P = 0.0002) with overall survival. Multivariate Cox analysis performed to correct these results for relative impact of the uPA system and established prognostic factors showed PAI-1 (disease-free survival: P = 0.002, relative risk 1.86; overall survival: P = 0.005, relative risk 1.39), pT and pN as independent parameters. Cathepsin D was shown to have an independent impact on disease-free survival (P = 0.020, relative risk 2.98). Comparative chi-square analysis of cases with poor and good prognoses revealed that in patients with good clinical outcome, inhibitors of proteolysis are correlated significantly, whereas in patients with poor prognosis activators of proteolysis are significantly associated preferentially and significant correlations with the uPA-R are dominan t. For detailed pattern analysis, stepwise overall Kaplan-Meier analyses were performed in subgroups of high uPA-R-, uPA-, PAI-1-and cathepsin D expression for two additional proteases each. From these analyses, the combination of high (score 2/3) expression of uPA-R, PAI-1, antichymotrypsin and a-2-macroglobulin was identified as a high-risk pattern, representing parameters known to be essential for uPA-R internalization and recycling. This suggests some of the uPA-associated proteases and inhibitors investigated as univariate prognostic parameters in gastric cancer. Cathepsin D is a new independent parameter for disease-free survival. The study further demonstrates that a protease pattern promoting uPA-R recycling in tumor cells especially indicates high individual risk tumors in gastric cancer. © Rapid Science 1998     

Vascular proliferation is associated with survival in pancreatic ductal adenocarcinoma

In pancreatic ductal adenocarcinoma (PDAC), the benefit of current chemotherapy and radiation therapy is very limited, even in radically resected patients. New treatment strategies, for example based on the inhibition of the tumour's blood supply, need to be explored. We have investigated angiogenesis markers and their associations with relapse and survival in 52 histologically confirmed cases of PDAC. Angiogenesis in the primary tumour was evaluated by microvessel density (MVD), vascular proliferation index (VPI) and the presence of glomeruloid microvascular proliferations (GMP). These features were analysed in the context of clinicopathological variables, KRAS mutation status, relapse location and survival. MVD (median 134 microvessels/mm², range 88–177) and VPI (median 3.2%, range 1.6–4.9) were associated with larger tumour size and lymph node metastasis. MVD was also related to the occurrence of liver metastases. Both variables were associated with survival in univariate and multivariate analyses. GMPs were present in 32 (62%) of the cases. Patients who exhibited MVD and VPI values above median, and GMP positivity, had a median survival of only 4.2 months after surgery. In conclusion, the angiogenesis markers MVD and VPI have a significant impact on survival. By also including GMP, a subgroup of PDAC patients with particularly short survival could be identified.     

Increased chemokine receptor IL-17RA expression is associated with poor survival in gastric cancer patients

Background: Previous researchers have identified that the chemokine interleukin-17 (IL-17) was associated with survival time of patients with gastric cancer, but the roles of its receptors (IL-17R) in gastric cancer remain unknown. Our studies were designed to clarify the function of IL-17RA and to explore their potential role in gastric cancer. Materials and methods: The expression of IL-17RA was determined in primary gastric cancer tissues (n=101) using Real-time RT-PCR, immunohistochemistry, and western blotting. To investigate the functional significance of IL-17RA expression, IL-17RA expression and clinical parameters, multivariate survival was analyzed in patients with gastric cancer. Results: IL-17RA was overexpression in gastric cancer tissues compared with adjacent normal tissues (P<0.05). The elevated expression level of IL-17RA was observed correlated significantly with tumor progression (P=0.003), Lymphatic invasion (P=0.019), lymphoid nodal status (P=0.001), distant metastasis (P<0.001) of gastric cancer patients, TNM stage (P=0.0013) and was one of the independent prognostic factors for patient’s overall survival. Conclusions: These results demonstrated that the expression of IL-17RA plays an important role in gastric cancer progression, migration and prognosis of gastric cancer. The IL-17-IL-17RA signaling mechanism may be a potential novel target.     

Molecular genetics of gastric adenocarcinoma in clinical practice

The molecular genetics of gastric carcinoma (GC) dictates their biology and clinical behavior. The two morphologically distinct types of gastric carcinoma by Lauren classification, i.e., intestinal and diffuse cell types, have a significant difference in clinical outcome. These two types of GC have different molecular pathogenetic pathways with unique genetic alterations. In addition to environmental and other etiologies, intestinal type GC is associated with Helicobacter pylori (H. pylori) infection and involves a multistep molecular pathway driving the normal epithelium to intestinal metaplasia, dysplasia, and malignant transformation by chromosomal and/or microsatellite instability (MSI), mutation of tumor suppressor genes, and loss of heterozygosity among others. Diffuse type shows no clear causal relationship with H. pylori infection, but is commonly associated with deficiency of cell-cell adhesion due to mutation of the E-cadherin gene (CDH1), and a manifestation of the hereditary gastric cancer syndrome. Thus, detection of CDH1 mutation or loss of expression of E-cadherin may aid in early diagnosis or screening of diffuse type GC. Detection of certain genetic markers, for example, MSI and matrix metalloproteinases, may provide prognostic information, particularly for intestinal type. The common genetic alterations may offer therapeutic targets for treatment of GC. Polymorphisms in Thymidylate synthase to metabolize 5-fluorouracil, glutathione S-transferase for degradation of Cisplatin, and amplification/overexpression of human epidermal growth factor receptor 2 targeted by monoclonal antibody Trastuzumab, are a few examples. P13K/Akt/mTOR pathway, c-Met pathways, epidermal growth factor receptor, insulin-like growth factor receptor, vascular endothelial growth factor receptor fibroblast growth factor receptor, and micro RNAs are several potential therapeutic biomarkers for GC under investigation.     

Dietary,lifestyle and clinicopathological factors associated with APC mutations and promoter methylation in colorectal cancers from the EPIC‐Norfolk study

The tumour suppressor APC is the most commonly altered gene in colorectal cancer (CRC). Genetic and epigenetic alterations of APC may therefore be associated with dietary and lifestyle risk factors for CRC. Analysis of APC mutations in the extended mutation cluster region (codons 1276‐1556) and APC promoter 1A methylation was performed on 185 archival CRC samples collected from participants of the European Prospective Investigation into Cancer (EPIC)‐Norfolk study, with the aim of relating these to high‐quality seven‐day dietary and lifestyle data collected prospectively. Truncating APC mutations (APC⁺) and promoter 1A methylation (PM⁺) were identified in 43% and 23% of CRCs analysed, respectively. Distal CRCs were more likely than proximal CRCs to be APC⁺ or PM⁺ (p = 0.04). APC⁺ CRCs were more likely to be moderately/well differentiated and microsatellite stable than APC^? CRCs (p = 0.05 and 0.03). APC⁺ CRC cases consumed more alcohol than their counterparts (p = 0.01) and PM⁺ CRC cases consumed lower levels of folate and fibre (p = 0.01 and 0.004). APC⁺ or PM⁺ CRC cases consumed higher levels of processed meat and iron from red meat and red meat products (p = 0.007 and 0.006). Specifically, CRC cases harbouring GC‐to‐AT transition mutations consumed higher levels of processed meat (35 versus 24 g/day, p = 0.04) and iron from red meat and red meat products (0.8 versus 0.6 mg/day, p = 0.05). In a logistic regression model adjusted for age, sex and cigarette‐smoking status, each 19 g/day (1SD) increment increase in processed meat consumption was associated with cases with GC‐to‐AT mutations (OR 1.68, 95% CI 1.03–2.75). In conclusion, APC⁺ and PM⁺ CRCs may be influenced by diet and GC‐to‐AT mutations in APC are associated with processed meat consumption, suggesting a mechanistic link with dietary alkylating agents, such as N‐nitroso compounds. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Rare missense variants in CHRNB4 are associated with reduced risk of nicotine dependence

Genome-wide association studies have identified common variation in the CHRNA5-CHRNA3-CHRNB4 and CHRNA6-CHRNB3 gene clusters that contribute to nicotine dependence. However, the role of rare variation in risk for nicotine dependence in these nicotinic receptor genes has not been studied. We undertook pooled sequencing of the coding regions and flanking sequence of the CHRNA5, CHRNA3, CHRNB4, CHRNA6 and CHRNB3 genes in African American and European American nicotine-dependent smokers and smokers without symptoms of dependence. Carrier status of individuals harboring rare missense variants at conserved sites in each of these genes was then compared in cases and controls to test for an association with nicotine dependence. Missense variants at conserved residues in CHRNB4 are associated with lower risk for nicotine dependence in African Americans and European Americans (AA P = 0.0025, odds-ratio (OR) = 0.31, 95% confidence-interval (CI) = 0.31-0.72; EA P = 0.023, OR = 0.69, 95% CI = 0.50-0.95). Furthermore, these individuals were found to smoke fewer cigarettes per day than non-carriers (AA P = 6.6 × 10(-5), EA P = 0.021). Given the possibility of stochastic differences in rare allele frequencies between groups replication of this association is necessary to confirm these findings. The functional effects of the two CHRNB4 variants contributing most to this association (T375I and T91I) and a missense variant in CHRNA3 (R37H) in strong linkage disequilibrium with T91I were examined in vitro. The minor allele of each polymorphism increased cellular response to nicotine (T375I P = 0.01, T91I P = 0.02, R37H P = 0.003), but the largest effect on in vitro receptor activity was seen in the presence of both CHRNB4 T91I and CHRNA3 R37H (P = 2 × 10(-6)).     

肠型胃癌不同发展阶段基因表达谱分析

目的研究肠型胃癌不同发展阶段基因表达谱的改变。方法应用基因芯片技术对3例肠型胃癌不同发展阶段基因表达特征进行检测分析。基因芯片包括576个cDNA克隆，其中包括506个靶克隆，51个是本课题组前期工作经消减杂交得到的克隆，另外455个克隆则根据它们在肿瘤中的作用而选取。应用Cluster和TreeView软件进行聚类分析，研究各种基因与胃癌发生发展不同阶段的关系。结果经基因芯片技术分析得到了181个差异表达基因，至少在胃癌发生发展的一个阶段其Cy5：Cy3的比值大于2或者小于0．5。其中48个基因上调，133个基因下调。聚类分析将差异表达基因分成了5个特征性的组，反映了不同阶段的基因表达特征。同时发现一些重要的差异表达基因，SEC23IP、LIPF、EST（BQ291520）、SLC5A1、PG、CXCR4、DICER1、SH3GL2以及IGF2R等。结论认识并发现了胃癌差异基因表达特征以及一些重要基因，对肠型胃癌发生发展及转移的进一步研究将具有重要作用。     

Smoking is associated with hypermethylation of the APC 1A promoter in colorectal cancer: the ColoCare Study

Smoking tobacco is a known risk factor for the development of colorectal cancer and for mortality associated with the disease. Smoking has been reported to be associated with changes in DNA methylation in blood and in lung tumour tissues, although there has been scant investigation of how epigenetic factors may be implicated in the increased risk of developing colorectal cancer. To identify epigenetic changes associated with smoking behaviours, we performed epigenome‐wide analysis of DNA methylation in colorectal tumours from 36 never‐smokers, 47 former smokers, and 13 active smokers, and in adjacent mucosa from 49 never‐smokers, 64 former smokers, and 18 active smokers. Our analyses identified 15 CpG sites within the APC 1A promoter that were significantly hypermethylated and 14 CpG loci within the NFATC1 gene body that were significantly hypomethylated (p LIS < 1 × 10⁻⁵) in the tumours of active smokers. The APC 1A promoter was hypermethylated in 7 of 36 tumours from never‐smokers (19%), 12 of 47 tumours from former smokers (26%), and 8 of 13 tumours from active smokers (62%). Promoter hypermethylation was positively associated with duration of smoking (Spearman rank correlation, ρ = 0.26, p = 0.03) and was confined to tumours, with hypermethylation never being observed in adjacent mucosa. Further analysis of adjacent mucosa revealed significant hypomethylation of four loci associated with the TNXB gene in tissue from active smokers. Our findings provide exploratory evidence for hypermethylation of the key tumour suppressor gene APC being implicated in smoking‐associated colorectal carcinogenesis. Further work is required to establish the validity of our observations in independent cohorts. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Hyaluronidase splice variants are associated with histology and outcome in adenocarcinoma and squamous cell carcinoma of the lung

Heterogeneity of hyaluronidase (HYAL) expression has been identified in tumors and shows promise as an indicator of disease progression. The expression profile of alternatively spliced forms of HYAL was evaluated in tumors and normal lung tissue from 69 resected tumors of patients with adenocarcinomas and squamous cell carcinomas. HYAL1-wild-type (wt) and variants 1 to 5, HYAL2-wt, and HYAL3-wt, and variants 1 to 3 were identified by polymerase chain reaction and direct sequencing. Different proportions of the 3 HYAL-wt and variants were expressed in tumor and normal lung tissues. HYAL1-wt was associated with a poorer prognosis and HYAL3-v1 with a better prognosis. HYAL splice variants are associated with histology and outcome, suggesting that strategies aimed at modulating their levels may be effective for lung cancer treatment.     

Natural killing activity is associated with progression of gastric cancer

Previously, we proposed a new analysis of natural killing activity, in which an individual effector/target cell ratio was employed for comparison according to the peripheral number of effector cells. In 51 patients with gastric cancer, the activity was studied using that modified analysis. Natural killing activity was activated in patients with early cancer, where tumor-cell invasion was restricted to the mucosa or the submucosa, even though in well-differentiated adenocarcinoma with invasion of the mucosa alone, the activity remained at the level of controls. In contrast, the activity in advanced cancer, where tumor cells infiltrated beyond the submucosa, came to be inactivated as the cancer progressed. These facts suggest that natural killing activity in patients with gastric cancer is closely associated with tumor invasion and that reactive activation of the activity against tumor is induced, at least, in some patients with early stage.     

Inactivating mutation of the pro-apoptotic gene BID in gastric cancer

There is evidence that deregulation of apoptosis is mechanistically involved in cancer development and somatic mutations of apoptosis-related genes have been reported in human cancers. BID, a pro-apoptotic member of the Bcl-2 family, interconnects the extrinsic apoptosis pathway initiated by death receptors to the intrinsic apoptosis pathway. To explore the possibility that genetic alterations of BID might be involved in the development of human cancers, this study analysed the entire coding region and all splice sites in the human BID gene in 67 advanced gastric carcinomas. Overall, four BID mutations (6.0%) were detected that consisted of one frameshift and three missense mutations. The tumour-derived BID mutants were expressed in 293T cells and it was found that, compared with wild-type BID, the frequency of apoptosis was significantly reduced in cells expressing the gene containing the frameshift mutation. Furthermore, expression of the inactivating frameshift mutant interfered with cell death by overexpression of death receptors, indicating that this mutant inhibits the extrinsic apoptosis pathway in a dominant-negative fashion. Also, the frameshift mutation rendered cancer cells resistant to apoptosis induced by the anti-cancer drug 5-fluorouracil (5-FU). This is the first report of BID gene mutation in human malignancy. The data suggest that such mutations occur rarely in gastric cancers and that only a small fraction of BID mutations may lead to the loss of its apoptotic function.     

CARD18在凋亡素基因转染的胃癌细胞的表达及其在临床样本中的检测和意义

目的 探讨caspase募集结构域家族成员18(CARD18)在凋亡素诱导胃癌细胞凋亡的机制及在胃癌发生发展中的作用.方法 运用二维凝胶电泳法分离凋亡素作用胃癌细胞后表达的差异蛋白质,通过基质辅助激光解吸附飞行时间质谱技术(MALDI-TOF-MS)和生物信息学方法确定其中部分差异蛋白质,RT-PCR和Western blot法检测CARD 18的表达,采用免疫组化检测56例胃癌组织及癌旁组织中CARD 18的表达,并分析其与胃癌临床病理参数的关系.结果 凋亡素处理后的胃癌细胞CARD18表达下调最明显,CARD18蛋白在胃癌组织中的表达明显高于癌旁组织(P＜0.05),且与胃癌的分化程度和淋巴结转移有关(P＜0.05).结论 CARD18可作为一个潜在的预后标志物和靶向标志物.