Aberrant methylation and loss expression of RKIP is associated with tumor progression and poor prognosis in gastric cardia adenocarcinoma

Raf kinase inhibitory protein (RKIP) has been identified as a member of a novel class of molecules which implicated in cancer progression and suppress the metastatic spread of tumors. The aim of this study was to investigate the promoter methylation and expression of RKIP, determine the prognostic significance of RKIP in gastric cardia adenocarcinoma (GCA). MSP approach and immunohistochemistry methods were used respectively to examine methylation status and protein expression of RKIP in GCA tissues. The frequency of RKIP methylation in GCA tumor tissues (62.1 %) was significantly higher than that in corresponding normal tissues (4.1 %) and was associated with TNM stage, histological differentiation, depth of invasion, LN metastasis, distant metastasis or recurrence, and upper gastrointestinal cancers (UGIC) family history. Positive staining of RKIP in GCA tumor tissues (34.5 %) was significantly decreased than that in corresponding normal tissues (84.1 %) and was associated with RKIP methylation. RKIP may act as a tumor suppressor gene in GCA by regulation of the Raf-1/MEK/ERK signaling pathway. GCA patients in stage III and IV, with positive UGIC family history, and hypermethylation and down-expression of RKIP were most likely to develop metastatic disease and also showed the worse survival. RKIP methylation in GCA was an independent prognostic marker for survival using multivariate Cox regression analysis (P = 0.04). In all, aberrant hypermethylation of RKIP may be one of the mechanisms that lead to loss or down expression of the gene in GCA especially in individuals with UGIC family history. Additionally, hypermethylation and loss of RKIP expression may be used as a marker to predict clinical outcome of GCA.     

Loss of WW domain-containing oxidoreductase expression in the progression and development of gastric carcinoma: clinical and histopathologic correlations

The purpose of this study is to investigate the role of the WW domain-containing oxidoreductase (WWOX) tumor suppressor that maps to the common fragile site FRA16D (16q23.3-24.1) during the development of gastric carcinoma (GC), we examined the altered expression of WWOX in GC cell lines and tissue samples as well as the effects of restoration of the WWOX gene into WWOX-deficient GC cells. All GC cell lines (HSC-45, HSC-57, HSC-59, MKN-7, and MKN-74) showed reduced WWOX expression at the mRNA and protein levels and hypermethylation at the WWOX regulatory site was detected in HSC-45 and HSC-59 cells. Interestingly, treatment with the deacetylating agent trichostatin A and the demethylating agent 5-aza-2′-deoxycytidine restored endogenous WWOX expression levels in HSC-59 cells. Restoration of the WWOX gene with Ad-WWOX into HSC-59 cells effectively suppressed cell growth and increased the population of cells in subG₁ DNA content. In GC tissue samples, the loss of WWOX expression was detected in 24 (33%) of 73 GC cases in accordance with the hypermethylation at the WWOX regulatory site. Surprisingly, negative immunoreactivity against WWOX showed a significant relationship with several clinicopathologic findings, including histology (P = 0.0001), depth of invasion (P = 0.0004), lymph node metastasis (P = 0.0003), vessel infiltration (lymphatic vessels, P = 0.0167 and venous vessels, P = 0.0005), and clinicopathologic stage (P = 0.001). These findings suggest that repression of WWOX expression may play an important role in stomach carcinogenesis. WWOX thus appears to be a good biomarker for molecular diagnosis of the grade of malignancy of GCs.     

WWOX,the FRA16D gene: A target of and a contributor to genomic instability

WWOX is one of the largest human genes spanning over 1.11 Mbp in length at chr16q23.1‐q23.2 and containing FRA16D, the second most common chromosomal fragile site. FRA16D is a hot spot of genomic instability, prone to breakage and for causing germline and somatic copy number variations (CNVs). Consequentially WWOX is frequent target for deletions in cancer. Esophageal, stomach, colon, bladder, ovarian, and uterine cancers are those most commonly affected by WWOX deep focal deletions. WWOX deletions significantly correlate with various clinicopathological features in esophageal carcinoma. WWOX is also a common target for translocations in multiple myeloma. By mapping R‐loop (RNA:DNA hybrid) forming sequences (RFLS) we observe this to be a consistent feature aligning with germline and somatic CNV break points at the edges and core of FRA16D spanning from introns 5 to 8 of WWOX. Germline CNV polymorphisms affecting WWOX are extremely common in humans across different ethnic groups. Importantly, structural variants datasets allowed us to identify a specific hot spot for germline duplications and deletions within intron 5 of WWOX coinciding with the 5′ edge of the FRA16D core and various RFLS. Recently, multiple pathogenic CNVs spanning WWOX have been identified associated with neurological conditions such as autism spectrum disorder, infantile epileptic encephalopathies, and other developmental anomalies. Loss of WWOX function has recently been associated with DNA damage repair abnormalities, increased genomic instability, and resistance to chemoradiotherapy. The described observations place WWOX both as a target of and a contributor to genomic instability. Both of these aspects will be discussed in this review.     

Tumor suppressor WWOX moderates the mitochondrial respiratory complex

Fragile site FRA16D exhibits DNA instability in cancer, resulting in diminished levels of protein from the WWOX gene that spans it. WWOX suppresses tumor growth by an undefined mechanism. WWOX participates in pathways involving aerobic metabolism and reactive oxygen species. WWOX comprises two WW domains as well as a short‐chain dehydrogenase/reductase enzyme. Herein is described an in vivo genetic analysis in Drosophila melanogaster to identify functional interactions between WWOX and metabolic pathways. Altered WWOX levels modulate variable cellular outgrowths caused by genetic deficiencies of components of the mitochondrial respiratory complexes. This modulation requires the enzyme active site of WWOX, and the defective respiratory complex‐induced cellular outgrowths are mediated by reactive oxygen species, dependent upon the Akt pathway and sensitive to levels of autophagy and hypoxia‐inducible factor. WWOX is known to contribute to homeostasis by regulating the balance between oxidative phosphorylation and glycolysis. Reduction of WWOX levels results in diminished ability to respond to metabolic perturbation of normal cell growth. Thus, the ability of WWOX to facilitate escape from mitochondrial damage‐induced glycolysis (Warburg effect) is, therefore, a plausible mechanism for its tumor suppressor activity. © 2015 Wiley Periodicals, Inc.     

Investigation of Cytotoxic T‐lymphocyte antigen 4 Polymorphisms in Gastric Cardia Adenocarcinoma

To assess the potential effects of Cytotoxic T‐lymphocyte antigen 4 (CTLA4) gene polymorphisms on susceptibility to gastric cardia adenocarcinoma (GCA), we genotyped four polymorphisms (rs733618 A>G, rs16840252 C>T, rs231775 G>A and rs3087243 G>A) in CTLA4 and calculated odds ratios (ORs) with the corresponding 95% confidence intervals (95% CIs) for the genotype and allele distributions between GCA cases and controls. The CTLA4 genotypes were determined by the polymerase chain reaction–ligase detection reaction (PCR‐LDR) analysis in 330 GCA patients and 608 unrelated cancer‐free controls. In this case–control study, there was no significant difference in the genotype and allele distributions of four CTLA4 polymorphisms between GCA patients and controls. However, haplotype association analysis indicated that compared with CTLA4 G_rs733618C_rs16840252G_rs231775C_rs3087243, CTLA4 G_rs733618C_rs16840252A_rs231775G_rs3087243 and A_rs733618C_rs16840252G_rs231775A_rs3087243 haplotypes conferred increased risks of GCA (OR = 6.46, 95% CI = 1.33–31.28; P = 0.012; both); however, CTLA4 A_rs733618C_rs16840252A_rs231775G_rs3087243 and A_rs733618T_rs16840252G_rs231775G_rs3087243 haplotypes conferred decreased risks of GCA (P = 0.001 and P = 0.011, respectively). These results highlight that the rare CTLA4 haplotypes may affect the development of GCA in the Chinese population.     

High‐resolution loss of heterozygosity screening implicates PTPRJ as a potential tumor suppressor gene that affects susceptibility to non‐hodgkin's lymphoma

We employed a Hidden‐Markov‐Model (HMM) algorithm in loss of heterozygosity (LOH) analysis of high‐density single nucleotide polymorphism (SNP) array data from Non‐Hodgkin's lymphoma (NHL) entities, follicular lymphoma (FL), and diffuse large B‐cell lymphoma (DLBCL). This revealed a high frequency of LOH over the chromosomal region 11p11.2, containing the gene encoding the protein tyrosine phosphatase receptor type J (PTPRJ). Although PTPRJ regulates components of key survival pathways in B‐cells (i.e., BCR, MAPK, and PI3K signaling), its role in B‐cell development is poorly understood. LOH of PTPRJ has been described in several types of cancer but not in any hematological malignancy. Interestingly, FL cases with LOH exhibited down‐regulation of PTPRJ, in contrast no significant variation of expression was shown in DLBCLs. In addition, sequence screening in Exons 5 and 13 of PTPRJ identified the G973A (rs2270993), T1054C (rs2270992), A1182C (rs1566734), and G2971C (rs4752904) coding SNPs (cSNPs). The A1182 allele was significantly more frequent in FLs and in NHLs with LOH. Significant over‐representation of the C1054 (rs2270992) and the C2971 (rs4752904) alleles were also observed in LOH cases. A haplotype analysis also revealed a significant lower frequency of haplotype GTCG in NHL cases, but it was only detected in cases with retention. Conversely, haplotype GCAC was over‐representated in cases with LOH. Altogether, these results indicate that the inactivation of PTPRJ may be a common lymphomagenic mechanism in these NHL subtypes and that haplotypes in PTPRJ gene may play a role in susceptibility to NHL, by affecting activation of PTPRJ in these B‐cell lymphomas. © 2013 Wiley Periodicals, Inc.     

Association of cytotoxic T‐lymphocyte associated protein 4 gene polymorphisms with the risk and prognosis of oesophageal cancer in a high‐incidence region from northern China

The most important anti‐tumour immune response is mediated by T lymphocytes. Cytotoxic T lymphocyte‐associated protein 4 (CTLA4) plays a critical role in the immune surveillance against tumours as an inhibitory immune checkpoint molecule of T‐cell activation. This study was designed to explore the association of CTLA4 polymorphisms with the susceptibility to oesophageal squamous cell carcinoma (ESCC) and prognosis of patients with ESCC in a high‐incidence population from northern China. CTLA4 rs5742909 C/T and rs231775 G/A single nucleotide polymorphisms (SNPs) were genotyped using polymerase chain reaction–ligase detection reaction (PCR‐LDR) method in 577 ESCC patients and 580 controls. Upper gastrointestinal cancer family history increased the risk of ESCC (the sex‐, age‐ and smoking status‐adjusted OR = 1.383, 95%CI = 1.094–1.749). The genotype frequencies of these two SNPs in the patients with ESCC were similar to that in the controls. Survival analyses were conducted in 204 patients with ESCC with five‐year survival information. The mean survival time of ESCC patients with rs231775 SNP A/A genotype in age over 60 years group was 23.2 months, significantly shorter than that of those with G/G genotype (47.3 months). The A/A genotype was associated with increased death risk of patients with ESCC older than 60 years (adjusted HR = 4.544, 95%CI = 1.913–10.790). CTLA4 rs231775 SNP might be used as genetic marker of worse prognosis for patients with ESCC over 60 years in a high‐incidence population from northern China.     

Global demethylation in loss of imprinting subtype of wilms tumor

Epigenetic abnormalities at the IGF2/H19 locus play a key role in the onset of Wilms tumor. These tumors can be classified into three molecular subtypes depending on the events occurring at this locus: loss of imprinting (LOI), loss of heterozygosity (LOH), or retention of imprinting (ROI). As IGF2 LOI is a consequence of aberrant methylation, we hypothesized that this subtype of Wilms tumors might display global abnormalities of methylation. We therefore analyzed the methylation status of satellite DNA, as a surrogate for global methylation in 50 Wilms tumor patients. Satellite methylation was quantified by a methylation‐sensitive quantitative PCR. We confirmed hypomethylation of both satellite α (Sat α) and satellite 2 (Sat 2) DNA in Wilms tumor samples compared with normal kidney. In addition, we found that LOI tumors, unlike ROI or LOH ones, showed concordant hypomethylation of both Sat α and Sat 2 DNA. This would suggest that the LOI subtype of Wilms tumor, which unlike other subtypes results from an epimutation, has a global deregulation of methylation mechanisms. © 2012 Wiley Periodicals, Inc.     

DNA methylation of FKBP5 and response to exposure‐based psychological therapy

Differential DNA methylation of the hypothalamic‐pituitary‐adrenal axis related gene FKBP5 has recently been shown to be associated with varying response to environmental influences and may play a role in how well people respond to psychological treatments. Participants (n = 111) received exposure‐based cognitive behavioural therapy (CBT) for agoraphobia with or without panic disorder, or specific phobias. Percentage DNA methylation levels were measured for the promoter region and intron 7 of FKBP5. The association between percentage reduction in clinical severity and change in DNA methylation was tested using linear mixed models. The effect of genotype (rs1360780) was tested by the inclusion of an interaction term. The association between change in DNA methylation and FKBP5 expression was examined. Change in percentage DNA methylation at one CpG site of intron 7 was associated with percentage reduction in severity (β = ?4.26, p = 3.90 × 10^?4), where a decrease in DNA methylation was associated with greater response to therapy. An interaction was detected between rs1360780 and changes in DNA methylation in the promoter region of FKBP5 on treatment outcome (p = .045) but did not survive correction for multiple testing. Changes in DNA methylation were not associated with FKBP5 expression. Decreasing DNA methylation at one CpG site of intron 7 of FKBP5 was strongly associated with decreasing anxiety severity following exposure‐based CBT. In addition, there was suggestive evidence that allele‐specific methylation at the promoter region may also be associated with treatment response. The results of this study add to the growing literature demonstrating the role of biological processes such as DNA methylation in response to environmental influences.     

Genetic variant of IL28B rs12979860, as predictive marker of interferon‐based therapy in Pakistani population

Hepatitis C virus (HCV) genotypes and genetic variants of interleukin 28B (IL28B) are significantly associated with interferon plus ribavirin treatment of HCV infection. We investigated the distribution of HCV genotypes and single‐nucleotide polymorphisms (SNPs) of IL28B (rs12979860 and rs8099917) in Pakistani population. IL28B genotyping was performed by allele‐specific PCR and restriction fragment length polymorphism PCR in 140 chronic hepatitis C patients (CHC) and 120 healthy controls. HCV genotype 3 (HCVG3) was the most prevalent genotype, 71.4% (n = 100/140) and with the highest treatment response of 90% (n = 90/100). The overall treatment response of all the HCV genotypes was 82% (n = 115/140). The distribution of IL28B rs12979860CC genotype in treatment responder and non‐responder groups was 40.8% (n = 47/115) and 16% (n = 4/25) respectively. IL28B rs12979860CC genotype demonstrated a significant correlation (p = 0.019) with interferon‐based therapy of HCV infection. However, there was no observed association of IL28B rs8099917 polymorphism with treatment response in CHC patients (p = 0.264). In conclusion, HCV genotypes and IL28B rs12979860 are predictive markers for the efficiency of interferon plus ribavirin combinational therapy of HCV infection. We recommend the inclusion of testing for these markers in the clinical criteria for decision making for HCV therapy in Pakistani population.     

The Correlation of Increased CRP Levels with NFKB1 and TLR2 Polymorphisms in the Case of Morbid Obesity

Morbid obesity (MO) is associated with an increase in circulating levels of systemic acute phase proteins such as C‐reactive protein (CRP). Toll‐like receptor is possible candidate for inflammatory responses which is mainly mediated by NFKB1. The aim of this study was to investigate the relationship between NFKB1 and Toll‐like receptor (TLR) 2 polymorphisms and the risk of MO in a Turkish population in the context of CRP serum levels which may contribute to susceptibility to the disease. We analysed the distribution of NFKB1‐94 ins/del ATTG rs28362491 and TLR2 Arg753Gln rs5743708 polymorphisms using PCR‐RFLP method and CRP serum levels using ELISA method in 213 MO and 200 healthy controls. The frequency of the ins/ins genotype and ins allele of rs28362491 was significantly higher in the patients compared to control group (P: 0.0309; P: 0.0421, respectively). Additionally, the frequency of GG genotype and G allele of rs5743708 was found to be statistically higher in the patient group (P: 0.0421; P < 0.0001, respectively). In addition, serum CRP levels (>20 mg/l) in MO patients with ins/ins genotype were significantly higher than in patients with del/ins genotype (P: 0.0309). Serum CRP levels were also higher in MO patients with GG genotype and G allele (P: 0.0001). According to combined analysis, the wild type of rs28362491 and rs5743708 polymorphisms (ins/ins/GG genotype) was also significantly higher in the patient group versus the control group when compared with the combined ins/ins/GA and del/ins/GA genotype (P < 0.0001). Therefore, our findings suggest that rs28362491 and rs5743708 polymorphisms were significantly associated with MO disease through acting by modulating serum CRP levels.     

The rs6983267 SNP and long non‐coding RNA CARLo‐5 are associated with endometrial carcinoma

The single nucleotide polymorphism (SNP) rs6983267 and cancer‐associated region long non‐coding RNA (CARLo‐5) are associated with various human cancers. This study aimed to investigate the expression of CARLo‐5 in endometrial carcinoma (EC) and its relationship with clinicopathological features and patient survival. The association of the rs6983267 SNP with EC risk and its involvement in the regulation of CARLo‐5 expression in EC were investigated. The rs6983267 SNP was genotyped by polymerase chain reaction (PCR) and ligase detection reaction in 543 EC patients and 584 controls. The expression of CARLo‐5 in 108 EC tissues and 66 normal endometrial tissues (NETs) was determined using quantitative real‐time PCR. The genotype and allele distributions of the rs6983267 SNP differed significantly between patients and controls. There was a significant correlation between the rs6983267 genotypes and lymph node metastasis of EC patients (P = 0.026). CARLo‐5 expression was significantly higher in EC tissues than in NETs (P < 0.001) and significantly associated with FIGO stage (P = 0.029) and lymph node metastasis (P = 0.030). Patients with high CARLo‐5 expression had significantly shorter overall survival than those with low CARLo‐5 expression (P = 0.003). The rs6983267 genotype was significantly correlated with CARLo‐5 expression (P < 0.05). In conclusion, CARLo‐5 was identified as a pro‐oncogenic lncRNA that may play an important role in EC progression and represent a prognostic marker for EC. The expression of CARLo‐5 was significantly correlated with the rs6983267 genotype associated with increased susceptibility to EC. Environ. Mol. Mutagen. 57:508–515, 2016. © 2016 Wiley Periodicals, Inc.     

High frequency of RASSF1A and RARb2 gene promoter methylation in morphologically normal endometrium adjacent to endometrioid adenocarcinoma

Aims: To identify a DNA methylation signature of endometrioid carcinoma of the endometrium (EEC) in the early stages of endometrial carcinogenesis. Methods and results: Archival biopsy specimens of 39 EECs, 14 cases of atypical hyperplasia (AH), 11 histologically normal endometrial tissues adjacent to EECs and 24 normal control endometrial samples were retrieved. The cases were tested by quantitative methylation‐specific polymerase chain reaction with primers hybridizing in the promoter regions of five genes frequently methylated in human cancer (RASSF1A, RARb2, P16, MGMT and GSTPi). Twenty‐nine of 39 (74%) EECs and 7/14 (50%) AHs were methylated for the RASSF1A gene, whereas 17/39 (44%) EECs and 6/14 (43%) AHs were positive for the methylation of the RARb2 gene. No significant results were obtained for the other genes (P16, MGMT and GSTPi). Interestingly, 4/11 (36%) and 6/11 (55%) histologically normal endometrial tissues adjacent to EEC showed, respectively, RASSF1A and RARb2 gene methylation. Furthermore, these 11 specimens were microsatellite stable and showed similar proliferative, cell cycle and apoptotic mean labelling indices as the normal endometrial control tissues. Conclusions: Promoter region methylation of RASSF1A and RARb2 genes is an early event in endometrial carcinogenesis.     

Loss of heterozygosity at chromosome segment Xq25-26.1 in advanced human ovarian carcinomas

To determine whether a tumor suppressor gene of importance to epithelial ovarian cancer resides on the X chromosome, we examined loss of heterozygosity (LOH) in 123 epithelial ovarian cancer cases. In 54 such cases, we examined LOH at 26 loci on the human X chromosome. In eight cases, we examined LOH in 14 loci and in 61 cases we examined LOH in 13 loci. Matched DNA samples from tumors and corresponding normal tissues were analyzed by polymerase chain reaction (PCR) amplification of microsatellite markers. Frequent losses were found in epithelial carcinomas at the Xq25-26.1 region, including DXS1206(34.5% loss in informative cases), DXS1047(27.7%), HPRT(24.1%), and DXS1062 (33.3%). The minimum overlapping region of LOH was approximately 5 megabases (Mb), flanked by DXS1206(Xq25) and HPRT(Xq26.1). The methylation status of the remaining allele of the androgen receptor gene in the tumors exhibiting LOH at the Xq25-26.1 region suggested that the loss was exclusively in the inactive X chromosome. We next determined whether a significant relationship exists between Xq LOH and other parameters, including histologic grade and/or clinical stage of the tumors and LOH at TP53. The Xq LOH had a significant association with grade 2 to 3 tumors at stages II to IV. Sixteen of 18 cases that showed Xq LOH revealed LOH at the TP53 locus, and 45% of tumors exhibiting LOH at TP53 showed Xq LOH. These results suggest that there may be a tumor suppressor gene or genes which escape inactivation of the X chromosome at Xq25-26.1, and that the loss of the gene(s) at Xq25-26.1 is frequently accompanied by loss of the TP53 or loss of another gene on chromosome 17. These losses may contribute to the progression from a well-differentiated to a more poorly differentiated state or to metastatic aggressiveness. Genes Chromosomes Cancer 20:234–242, 1997. Published 1997 Wiley-Liss, Inc.     

Association analysis of polymorphisms in OAS1 with susceptibility and severity of hand,foot and mouth disease

Hand, foot and mouth disease (HFMD) is a common childhood illness that mainly affects Asian children under the age of 5 years. Human enterovirus 71 (EV71) and coxsackievirus A16 (CA16) are the most common pathogens of HFMD. It is imperative that the susceptible population is screened early and that the severe illness population can be identified via genetic variation detection in children. Four single‐nucleotide polymorphisms (SNP) [2′‐5′‐oligoadenylate synthetase1 (OAS1) rs10774671, selectin P ligand (SELPLG) rs2228315, scavenger receptor class B member 2 (SCARB2) rs41284767 and interleukin 28B (IL28B) rs12979860] were determined by Taqman assays in 333 HFMD samples and 163 control samples. The rs2228315, rs41284767 and rs12979860 polymorphisms did not differ significantly between HFMD patients and the controls, but the prevalence of the rs10774671 polymorphism was significantly different between the control children and children infected with CA16 (GG genotype vs. AA + AG genotype, P < 0.05). Children with the GG genotype were more susceptible to CA16‐type HFMD. Furthermore, the rs10774671 genotype distribution was clearly different between children with severe HFMD and those with mild HFMD [P < 0.05, OR 0.240, 95% CI (0.071–0.809)]. HFMD children with the AA+AG genotype were more likely to progress to encephalitis than were those with the GG genotype. Plasma γ‐interferon (IFN) expression levels among control children and the mild and severe HFMD children were detected by ELISA. Those with mild HFMD had higher γ‐IFN expression levels compared with those with severe HFMD (P < 0.05). In addition, there is a significant correlation between γ‐IFN levels and OAS1 rs10774671 SNP, as analysed by linear correlation assay. The GG genotype correlated with higher γ‐IFN levels (P < 0.05). In short, the OAS1 rs10774671 SNP GG genotype contributed to CA16 susceptibility and was associated with the development of mild HFMD.     

中国人胃癌骨形态发生蛋白3基因遗传的不稳定和甲基化

目的 探讨骨形态发生蛋白3(BMP3)基因遗传不稳定性及异常甲基化与胃癌进展的关系,为揭示BMP3基因作用机制和胃癌发生发展机制提供实验依据. 方法 采用聚合酶链反应-单链构象多态(PCR-SSCP)技术分析中国人胃癌BMP3基因D4S2922、 D4S2964位点微卫星不稳定性(MSI)和杂合性缺失(LOH);使用甲基化特异PCR法检测BMP3基因启动子的甲基化状况. 结果 在本实验中,50例胃癌标本BMP3基因微卫星位点MSI、 LOH的阳性率分别为16.00%和20.00%,并且LOH检出率在胃癌的TNM Ⅲ+Ⅳ期高于Ⅰ+Ⅱ期(P<0.01),并随淋巴转移的发生而增高(P<0.01).45例胃癌标本中BMP3基因启动子区域甲基化阳性率为64.44%,其检出率与胃癌分化程度、浆膜浸润、淋巴转移及TNM分期均无关.此外,MSI阴性组的甲基化阳性率为71.05%, 显著高于MSI阴性组的28.58%(P<0.05). 结论 BMP3基因遗传不稳定和启动子甲基化存在于胃癌的发生发展中.LOH多发生于胃癌的晚期阶段并赋予胃癌高侵袭、预后差的表型.BMP3基因启动子高甲基化可能是胃癌发生因素之一.     

Associative role of HLA‐DRB1 SNP genotypes as risk factors for susceptibility and severity of rheumatoid arthritis: A North‐east Indian population‐based study

Rheumatoid arthritis (RA) is a complex, multifactorial, systemic autoimmune disease. Reports are suggestive of the role of HLA especially HLA‐DRB1 alterations in RA pathogenesis. Existing data involving different geographical populations on the role of alterations in specific locus of HLA‐DRB1 in RA susceptibility and severity are equivocal, with no data available from ethnically distinct North‐east Indian population, where RA cases are alarmingly increasing. This study aimed to evaluate the association of HLA‐DRB1 gene SNPs (rs13192471, rs660895 and rs6457617) with susceptibility and severity of RA in an ethnically distinct North‐east Indian population. Whole blood was collected from clinically characterized RA cases (satisfying the American College of Rheumatology 1987 criteria) (n = 123) and community‐based age and sex‐matched healthy controls (n = 156) with informed consent. The HLA‐DRB1 SNP analysis was performed for all the RA and control cases using ARMS‐PCR using case and control genomic DNA as template. Statistical analysis was performed by SPSSv13.0 software. The HLA‐DRB1 rs660895 showed both wild (AA) and heterozygote (AG) genotype but the heterozygote allele was found to be associated with reduced risk of RA compared to controls [OR = 0.531, p = .024]. The difference in distribution of rs6457617 polymorphism between RA and control cases was comparable [OR = 0.525, p = .079]. Significantly higher distribution of variant rs13192471 genotype was observed in RA cases (69.92%) compared to controls (46.75%) (p < .001) and was associated with increased risk of susceptibility to RA [OR = 2.576, p < .001] compared to controls, as well as progression to severity in RA cases [OR = 2.404, p = .048]. Combinatorially also, the presence of rs13192471 variant genotype was associated with increased risk of RA susceptibility [OR = 8.267, p = .026] and RA severity [OR = 3.647, p = .280]. Alterations in HLA‐DRB1 are associated with RA susceptibility. HLA‐DRB1 rs13192471 SNP plays a critical role in RA susceptibility and severity in North‐east Indian cases and has prognostic significance in RA.