Association between mutations in the CARD15/NOD2 gene and colorectal cancer in a Greek population

Low-Penetrance Susceptibility Variants in Colorectal Cancer-Current Outlook in the Field

Colorectal cancer (CRC) is one of the most frequent and mortality-causing neoplasia, with various distributions between populations. Strong hereditary predispositions are the causatives of a small percentage of CRC, and most cases have no transparent genetic background. This is a vast arena for exploring cancer low-susceptibility genetic variants. Nonetheless, the research that has been conducted to date has failed to deliver consistent conclusions and often features conflicting messages, causing chaos in this field. Therefore, we decided to organize the existing knowledge on this topic. We screened the PubMed and Google Scholar databases. We drew up markers by gene locus gathered by hallmark: oncogenes, tumor suppressor genes, genes involved in DNA damage repair, genes involved in metabolic pathways, genes involved in methylation, genes that modify the colonic microenvironment, and genes involved in the immune response. Low-penetration genetic variants increasing the risk of cancer are often population-specific, hence the urgent need for large-scale testing. Such endeavors can be successful only when financial decision-makers are united with social educators, medical specialists, genetic consultants, and the scientific community. Countries' policies should prioritize research on this subject regardless of cost because it is the best investment. In this review, we listed potential low-penetrance CRC susceptibility alleles whose role remains to be established.

NOD2 and Crohn's Disease Clinical Practice: From Epidemiology to Diagnosis and Therapy, Rewired

Crohn's disease (CD) is a chronic inflammatory bowel disease with a multifactorial pathogenesis involving environmental and genetic factors. Since the late 20th century, the discovery of the first susceptibility gene (NOD2, previously referred to as CARD15) for CD has paved the way for further investigations into the correlations between clinical features and genetics, and its potential impact on clinical practice has fueled the research in the last 2 decades. Recent therapeutic advancements involving novel biologic drugs and small molecules have shifted inflammatory bowel disease management from a disease-centered to a patient-centric approach. To date, the role of NOD2 has not been fully understood yet. Recent data suggest that its clinical impact may be greater than currently recognized. This review overviews the most common NOD2 variants' role in real-life clinical practice. These genetic variants increase the risk of developing the disease and can aid in tailoring diagnosis and treatment. They are associated with the stricturing phenotype and ileal involvement and increase the risk of steroid refractoriness. In the meantime, limited and inconclusive evidence exists regarding their predictive role in response to azathioprine, biologic drugs, and small molecules. Eventually, their role in increasing the risk for surgery is evident, especially in those with the L1007fs variant. If further trials will support the initial evidence reported so far, NOD2 genetic variants will emerge as possible candidates for developing precision medicine in CD.

Metastatic colorectal cancer in both sides of Aegean sea: practice patterns and outcome

OBJECTIVE

The successful results obtained in trials may not necessarily translate into prolonged survival of metastatic colorectal cancer (mCRC) patients in real life. This multinational registry study aimed to evaluate the real-life data effecting the survival of patients with mCRC.

METHODS

This is a multinational, retrospective registry study. Turkish and Greek mCRC patients diagnosed between 2005 and 2012, with at least 3 years of follow-up data or who died before 3 years of follow-up were included in the study.

RESULTS

A total of 364 were included in the study. RAS and BRAF mutation rates were found to be 36% and 39%, respectively. As first-line therapy, 196 (54%) patients received bevacizumab and Anti-EGFR treatments in combination with chemotherapy. The objective response rate was 42% (n = 152) and 32% (n = 78) for 1^st line and 2^nd line treatments, respectively. While the median progression-free survival (PFS) with the 1^st line treatment was 10 months, it was 7 months with the 2^nd line treatments. In the total study population median PFS and overall survival (OS) were 10 (95% CI, 8.3-11.6) and 35 (95% CI, 30.7-39.2) months, respectively. In Turkish and Greek patients, median OS (36 months versus 29 months, p = .81) and PFS (10.2 versus 9.2, p = .42) were not different. In multivariate analysis, ECOG PS of ≥2 and having metastases in more than one region decreased overall survival (p = .002 and p = .003), it was found that wild RAS and BRAF mutations and second metastasectomy contributed to overall survival (p = .047 and p < .001).

CONCLUSION

In conclusion, it seems that the patient's performance status, tumor location, number of metastatic lesions at the time of diagnosis affect the prognosis of mCRC. Although access to molecular tests and first-line treatments differ between Greece and Turkey, no significant difference was found in survival times.

The Association between Nod2 R702w Polymorphism and Susceptibility to Colorectal Cancer in Romanian Patients

It is well recognized that the inflammatory bowel disease (IBD) is associated with an increased risk of colorectal cancer (CRC). More susceptibility IBD genes have been reported, NOD2 being one of the most extensively investigated. The aim of this study was to evaluate a possible correlation between NOD2 rs2066844 C>T (also known as Arg702Trp or R702W) variant and CRC risk in a Romanian population. A total of 373 Romanian subjects (108 patients diagnosed with sporadic CRC and 265 controls) were enrolled in this hospital-based case-control study. The NOD2 R702W variants were detected by Real-time PCR using a predesigned TaqMan Genotyping Assay. The association between the genetic risk variant and CRC was expressed as odds ratios (OR) with 95% confidence intervals (CI). We did not find any statistically significant difference when we compared CC genotype with CT genotype (OR 1.1, 95% CI: 0.46-2.61; p=0.83) between CRC patients and controls. No TT homozygous genotype was detected. Also, we compared allele frequencies and no correlation was found (OR 1.09, 95% CI: 0.47-2.56; p=0.84). No association was found in the stratified analysis by tumor site, Dukes' stage and histological subtype. Our study suggests that the NOD2 R702W variant is not associated with CRC risk in the Romanian population. Further data from different and larger populations is required to determine whether NOD R702W SNP has effects on susceptibility to CRC.

NOD2 Expression in Intestinal Epithelial Cells Protects Toward the Development of Inflammation and Associated Carcinogenesis

Nucleotide-binding oligomerization domain 2 (NOD2) is an intracellular pattern recognition receptor that senses bacterial peptidoglycan-conserved motifs in cytosol and stimulates host immune response including epithelial and immune cells. The association of NOD2 mutations with a number of inflammatory pathologies including Crohn's disease (CD), graft-versus-host diseases, or Blau syndrome, highlights its pivotal role in inflammatory response and the associated-carcinogenesis development. Since its identification in 2001 and its association with CD, the role of NOD2 in epithelial cells and immune cells has been investigated extensively but the precise mechanism by which NOD2 mutations lead to CD and the associated carcinogenesis development is largely unknown. In this review, we present and discuss recent developments about the role of NOD2 inside epithelial cells on the control of the inflammatory process and its linked carcinogenesis development.

NOD2 Suppresses Colorectal Tumorigenesis via Downregulation of the TLR Pathways

Although NOD2 is the major inflammatory bowel disease susceptibility gene, its role in colorectal tumorigenesis is poorly defined. Here, we show that Nod2-deficient mice are highly susceptible to experimental colorectal tumorigenesis independent of gut microbial dysbiosis. Interestingly, the expression of inflammatory genes and the activation of inflammatory pathways, including NF-κB, ERK, and STAT3 are significantly higher in Nod2^-/- mouse colons during colitis and colorectal tumorigenesis, but not at homeostasis. Consistent with higher inflammation, there is greater proliferation of epithelial cells in hyperplastic regions of Nod2^-/- colons. In vitro studies demonstrate that, while NOD2 activates the NF-κB and MAPK pathways in response to MDP, it inhibits TLR-mediated activation of NF-κB and MAPK. Notably, NOD2-mediated downregulation of NF-κB and MAPK is associated with the induction of IRF4. Taken together, NOD2 plays a critical role in the suppression of inflammation and tumorigenesis in the colon via downregulation of the TLR signaling pathways.

Chronic Inflammation Links Cancer and Parkinson's Disease

An increasing number of genetic studies suggest that the pathogenesis of Parkinson's disease (PD) and cancer share common genes, pathways, and mechanisms. Despite a disruption in a wide range of similar biological processes, the end result is very different: uncontrolled proliferation and early neurodegeneration. Thus, the links between the molecular mechanisms that cause PD and cancer remain to be elucidated. We propose that chronic inflammation in neurons and tumors contributes to a microenvironment that favors the accumulation of DNA mutations and facilitates disease formation. This article appraises the key role of microglia, establishes the genetic role of COX2 and CARD15 in PD and cancer, and discusses prevention and treatment with this new perspective in mind. We examine the evidence that chronic inflammation is an important link between cancer and PD.

NOD2 mutations and colorectal cancer - Where do we stand?

Due to the overwhelming burden of colorectal cancer (CRC), great effort has been placed on identifying genetic mutations that contribute to disease development and progression. One of the most studied polymorphisms that could potentially increase susceptibility to CRC involves the nucleotide-binding and oligomerization-domain containing 2 (NOD2) gene. There is growing evidence that the biological activity of NOD2 is far greater than previously thought and a link with intestinal microbiota and mucosal immunity is increasingly sought after. In fact, microbial composition may be an important contributor not only to inflammatory bowel diseases (IBD) but also to CRC. Recent studies have showed that deficient NOD2 function confers a communicable risk of colitis and CRC. Despite the evidence from experimental models, population-based studies that tried to link certain NOD2 polymorphisms and an increase in CRC risk have been described as conflicting. Significant geographic discrepancies in the frequency of such polymorphisms and different interpretations of the results may have limited the conclusions of those studies. Since being first associated to IBD and CRC, our understanding of the role of this gene has come a long way, and it is tempting to postulate that it may contribute to identify individuals with susceptible genetic background that may benefit from early CRC screening programs or in predicting response to current therapeutic tools. The aim of this review is to clarify the status quo of NOD2 mutations as genetic risk factors to chronic inflammation and ultimately to CRC. The use of NOD2 as a predictor of certain phenotypic characteristics of the disease will be analyzed as well.

NOD2 Arg702Trp Polymorphism in Romanian Patients with Gastric Cancer

Purpose. Our study aimed to assess a possible correlation between NOD2 Arg702Trp (rs2066844) polymorphism and gastric cancer risk in a Romanian population. Material/Methods. A total of 322 subjects (72 patients with gastric adenocarcinoma and 250 healthy controls) were included. Genomic DNA was extracted from blood leukocytes and NOD2 Arg702Trp polymorphism was genotyped by Real-Time PCR using specific TaqMan probes. Results. No statistically significant difference was observed between gastric cancer patients and controls when we compared one genotype with other genotype (the CC genotype serves as reference) (OR 0.45, 95% CI: 0.10 - 2.05) or when we compared allele frequencies (the C allele serves as reference) (OR 0.46, 95% CI: 0.11 - 2.04). We examined separately the association of this polymorphism with tumor site and histologic type and no correlation was found. Conclusion. NOD2 Arg702Trp polymorphism is not associated with gastric cancer risk and further investigations are needed to elucidate the contribution of NOD2 gene in gastric carcinogenesis.

The immune microenvironment of the colorectal tumor: Involvement of immunity genes and microRNAs belonging to the TH17 pathway

Colorectal cancer is a complex and multifactorial disease. Various factors such as genetic, immunological, epigenetic and environmental constitute minor risk factors with their additive effects contributing to the advent of colorectal cancer. In order to evaluate the role of innate and adaptive immunity in the susceptibility, the presentation and the development of colorectal cancer, we considered an immunogenetic approach on polymorphisms in the TLR4 gene and NOD2/CARD15 gene (receptors of innate immunity) as well as in cytokine genes of the TH17 pathway IL17A, IL17F and cytokine receptor IL23R. Then, we evaluated the expression of microRNAs regulated by TLR4 and NOD2/CARD15 or targeting TLR4, IL17 and proinflammatory cytokines (IL-6, TNF) induced by IL17. Through a case-control study, we showed that the polymorphism of IL17A is associated with its susceptibility to colorectal cancer. Considering the tumor location, we found that the mutated alleles of IL17A, IL17F and IL23R are rather associated with colon cancer and not with rectum cancer. This result confirms that the colon and rectum are two different physiological entities. This study shows that TLR4, IL17A/F and IL23R polymorphisms are involved in the presentation of the disease with regard to tumor architecture, histology, and differentiation, advanced stage of the disease and lymph node and metastasis. Overall, these polymorphisms are associated with a poor prognosis of the disease. Furthermore, in order to evaluate the involvement of epigenetic mechanisms in the occurrence of colorectal cancer, we aimed at analyzing the tumor compared to a normal adjacent tissue and the expression of miRNAs (miR21, miR146a, miR135a, miR147b and miR155) that regulate immunity genes especially the cytokines of the TH17 pathway. This research has shown that microRNAs 21, 135a and 146a are associated with colorectal cancer. Indeed, these three miRs are overexpressed in cancer tissue compared to healthy tissue. These results clearly confirm the involvement of epigenetics in colorectal cancer. In other words, this study reveals the importance of immunity and specifically the TH17 pathway in the development and presentation of colorectal cancer. These results suggest that TLR4, IL17A, IL17F and IL23R polymorphisms as well as the expression of microRNAs that regulate inflammation and the TH17 pathway are associated with the evolution and progression of the colorectal tumor that could be considered as biomarkers in colorectal cancer.

A comprehensive analysis of candidate genes and pathways in pancreatic cancer

The study aimed to dissect the molecular mechanism of pancreatic cancer by a range of bioinformatics approaches. Three microarray datasets (GSE32676, GSE21654, and GSE14245) were downloaded from Gene Expression Omnibus database. Differentially expressed genes (DEGs) with logarithm of fold change (|logFC|) >0.585 and p value <0.05 were identified between pancreatic cancer samples and normal controls. Transcription factors (TFs) were selected from the DEGs based on TRASFAC database. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed for the DEGs using The Database for Annotation, Visualization and Integrated Discovery (p value <0.05), followed by construction of protein-protein interaction (PPI) network using Search Tool for the Retrieval of Interacting Genes software. Latent pathway identification analysis was applied to analyze the DEGs-related pathways crosstalk and the pathways with high weight value were included in the pathway crosstalk network using Cytoscape. Sixty-five DEGs were screened out. CCAAT/enhancer-binding protein delta (CEBPD), FBJ osteosarcoma oncogene B (FOSB), Stratifin (SFN), Krüppel-like factor 5 (KLF5), Pentraxin 3 (PTX3), and nuclear receptor subfamily 4, group A, member 3 (NR4A3) were important TFs. Interleukin-6 (IL-6) was the hub node of the PPI network. DEGs were significantly enriched in NOD-like receptor signaling pathway which was primarily interacted with inflammation and immune related pathways (cytosolic DNA-sensing, hematopoietic cell lineage, intestinal immune network for IgA production and chemokine pathways). The study suggested CEBPD, FOSB, SFN, KLF5, PTX3, NR4A3, IL-6, and NOD-like receptor pathways were involved in pancreatic cancer.

A miRNA-binding site single nucleotide polymorphism in the 3'-UTR region of the NOD2 gene is associated with colorectal cancer

Colorectal cancer (CRC) is one of the common malignancies worldwide. Single nucleotide polymorphisms in miRNA-binding site on gene transcripts are reported to play important role in increased risk of CRC in different population. We performed a case-control study using 88 CRC patients and 88 non-cancer counterparts to evaluate the association between NOD2 rs3135500 polymorphism located at 3' untranslated region of the gene and risk of sporadic CRC. Genotyping of rs3135500 polymorphism was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. We found a significant association of AA genotype with risk of CRC (adjusted OR 3.100, CI 1.621-5.930, p < 0.001). Also, significant difference in physical activity (p = 0.001) between case and control groups was found. We also found that individuals in control group were more aspirin or NSAID user compared to sporadic CRC cases (p = 0.002). In the case group, individuals with GG genotype consumed more aspirin or NSAID compared with AA+AG genotypes (33.3 vs. 9.6 %, adjusted OR 4.71, CI 1.25-17.76, p = 0.02). However, in the control group, individuals with AA+AG genotypes used more aspirin or NSAID compared with GG genotypes (47.2 vs. 11.4 %, adjusted OR 14 %, CI 0.05-0.47, p < 0.001).

3020insC NOD2/CARD15 polymorphism associated with treatment of colorectal cancer

Chronic inflammation is closely linked to cancer. The risk of damage by colorectal cancer (CRC) may increase due to autoimmune disease and cryptogenic inflammation. Therefore, genetic factors implicated in the chronic irritation in inflammatory bowel disease such as NOD2/CARD15 may predispose to CRC. In this report, we shed the light on the possible contribution of the NOD2 3020insC variant to CRC risk in a series of 246 Tunisian subjects including 101 patients with CRC and 145 healthy controls. NOD2/CARD15 polymorphism was genotyped by sizing fluorescently labeled PCR products and automated sequencers. We analyzed the association between the molecular features at this gene in relation to tumor and patient characteristics and treatments. Through this qualitative analysis, we found that CRC patients with mutant allele of NOD2/CARD15 were suffering from Crohn's disease (CD) with canonic presentation. We also observed a positive association between 3020insC polymorphism and surgery and chemotherapy. We suppose that around 3% of colorectal cases which happen at an age older than 50 years are associated with the canonic form of CD along with the 3020insC mutation and that these patients are in need for chemotherapy.

NOD2 polymorphisms associated with cancer risk: a meta-analysis

BACKGROUND

Emerging evidence indicated that common polymorphisms of NOD2 might impact individual susceptibility to cancer. However, the results from published studies were inconclusive. The aim of this meta-analysis was to elucidate whether NOD2 polymorphisms were associated with cancer risk.

METHODS

A systematically literature search was performed by using electronic databases including PubMed and Web of Science. ORs and their 95% CI were used to assess the strength of association between NOD2 gene polymorphisms and cancer risks.

RESULTS

Thirty case-control studies were included in this meta-analysis. The pooled analysis indicated that NOD2 rs2066842 C/T polymorphism was not significantly associated with cancer risk; for NOD2 rs2066844 C/T polymorphism, (TT+CT) genotype was associated with increased cancer risk compared with wild-type CC genotype (OR = 1.32, 95% CI = 1.01-1.72, P = 0.041); for NOD2 rs2066845 C/G polymorphism, individuals with (CC+CG) genotype were significantly associated with increased cancer risk compared with GG genotype (OR = 1.32, 95% CI = 1.01-1.72, P = 0.040); for NOD2 rs2066847 (3020insC) polymorphism, carriers of (insC/insC+insC/-) genotype were significantly associated with increased cancer risk compared with -/- carriers (OR = 1.23, 95% CI = 1.10-1.38, P<0.001). In the subgroup analysis of cancer type, (insC/insC+insC/-) genotype was significantly associated with increased risk of colorectal cancer, gastric cancer and MALT lymphoma, breast cancer, lung cancer, laryngeal cancer but not with urogenital cancer, pancreatic cancer, melanoma or non-Hodgkin lymphoma.

CONCLUSION

NOD2 rs2066844 C/T, rs2066845 C/G and rs2066847 (3020insC) polymorphisms might be associated with increased cancer risk. No significant association was observed between NOD2 rs2066842 C/T polymorphism and cancer risk. Further large-scale and well-designed studies are still needed to confirm the results of our meta-analysis.

The genetics of innate immunity sensors and human disease

Since their discovery, innate immunity microbial sensors have been increasingly studied and shown to play a critical role in innate responses to microbes in several experimental in vitro, ex vivo, and animal models. However, their role in the human response to infection in natural conditions has just started to be deciphered, by means of clinical studies of primary immunodeficiencies and epidemiological genetic studies. Here, we summarize the major findings concerning the genetic diversity of the various families of microbial sensors in humans, and of other molecules involved in the signaling pathways they trigger. Specifically, we review the genetic associations, revealed by both clinical and epidemiological genetics studies, of microbial sensors from five different families: Toll-like receptors, C-type lectin receptors, NOD-like receptors, RIG-I-like receptors, and cytosolic DNA sensors. In particular, we consider the relationships between variation at the genes encoding these molecules and susceptibility to and the severity of infectious diseases and other clinical conditions associated with immune dysfunction, including autoimmunity, inflammation, allergy, and cancer. Despite the fact that the genetic links between innate immunity sensors and human disorders remain still limited, human genetics studies are increasingly improving our understanding of the genuine functions of microbial sensors and downstream signaling molecules in the natural setting.

Card15 mutations and gastric cancer in a Portuguese population

BACKGROUND. CARD15 is involved in the innate immune response and mutations of this gene have been linked with increased risk of Crohn's disease and colorectal cancer. The relation between CARD15 mutations and gastric cancer (GC) remains controversial. AIMS. To assess whether CARD15 mutations are risk factors for GC in Portugal and whether there are genotype-phenotype correlations in these patients. METHODS. The 3 main CARD15 mutations (3020insC, R702W and G908R) were searched in 150 patients with GC and in 202 healthy controls. RESULTS. Overall, CARD15 mutations were found in 28 patients (18.7%) and in 27 controls (13.4%) (p = 0.176). Individually, the incidence of 3020insC was significantly higher in patients than in controls (6.0% vs. 1.0%, p = 0.021). This polymorphism was linked with an increased risk for the intestinal-type of GC (p = 0.002), while no association was found with the diffuse and/or mixed types. Genotype frequencies for R702W (10.0% vs. 7.9%) and G908R (4.0% vs. 4.0%) were not statistically different between the two groups. Similarly, no significant associations were detected between these two polymorphisms and the different histological GC types. No correlations were observed between CARD15 mutations and family history, mean age at diagnosis or GC stage. CONCLUSIONS. The CARD15 3020insC variant is a risk factor for intestinal GC in Portugal. CARD15 variants are not correlated with age of diagnosis or family aggregation of the disease neither with the GC stage.

NOD2-mediated dysbiosis predisposes mice to transmissible colitis and colorectal cancer

Instability in the composition of gut bacterial communities (dysbiosis) has been linked to common human intestinal disorders, such as Crohn's disease and colorectal cancer. Here, we show that dysbiosis caused by Nod2 deficiency gives rise to a reversible, communicable risk of colitis and colitis-associated carcinogenesis in mice. Loss of either Nod2 or RIP2 resulted in a proinflammatory microenvironment that enhanced epithelial dysplasia following chemically induced injury. The condition could be improved by treatment with antibiotics or an anti-interleukin-6 receptor-neutralizing antibody. Genotype-dependent disease risk was communicable via maternally transmitted microbiota in both Nod2-deficient and WT hosts. Furthermore, reciprocal microbiota transplantation reduced disease risk in Nod2-deficient mice and led to long-term changes in intestinal microbial communities. Conversely, disease risk was enhanced in WT hosts that were recolonized with dysbiotic fecal microbiota from Nod2-deficient mice. Thus, we demonstrated that licensing of dysbiotic microbiota is a critical component of disease risk. Our results demonstrate that NOD2 has an unexpected role in shaping a protective assembly of gut bacterial communities and suggest that manipulation of dysbiosis is a potential therapeutic approach in the treatment of human intestinal disorders.

Association of NOD1 and NOD2 genes polymorphisms with Helicobacter pylori related gastric cancer in a Chinese population

AIM: To investigate the association between the tag single nucleotide polymorphisms (TagSNPs) of NOD1 and NOD2 and the risk of developing gastric cancer.

METHODS: We conducted a hospital-based case-control study including 296 incident gastric cancer patients and 160 gastritis controls. Eight TagSNPs in the NOD1 and NOD2 genes were selected from the Hapmap database using the haploview software and genotyped by the Sequenom MassArray system. The serum levels of anti-Helicobacter pylori (H. pylori) IgG were measured by enzyme-linked immunosorbent assay to indicate H. pylori infection. The odds ratios (OR) and 95% confidence intervals (CI) were calculated by unconditional logistic regression, including sex and age as confounding factors.

RESULTS: The NOD1 rs2907749 GG genotype showed a decreased risk for gastric cancer (OR 0.50, 95% CI: 0.26-0.95, P = 0.04) while the rs7789045 TT genotype showed an increased risk (OR 2.14, 95% CI: 1.20-3.82, P = 0.01). An elevated susceptibility to gastric cancer was observed in the subjects with H. pylori infection and the NaOD1 rs7789045 TT genotype (OR 2.05, 95% CI: 1.07-3.94, P = 0.03) or the NOD2 rs7205423 GC genotype (OR 2.52, 95% CI: 1.05-6.04, P = 0.04). Haplotype analysis suggested that the distribution of AGT (rs2907749, rs2075820 and rs7789045) in NOD1 between the cases and control groups was significantly different (P corrected: 0.04), and the diplotype AGT/AGT was associated with an elevated gastric cancer risk (OR 1.98, 95% CI: 1.04-3.79, P = 0.04). The association of the NOD1 rs7789045 TT genotype and the diplotype AGT/AGT was significant with H. pylori-related diffuse-type gastric cancer (OR 3.00, 95% CI: 1.38-6.53, P = 0.01; OR 4.02, 95% CI: 1.61-10.05, P < 0.01, respectively).

CONCLUSION: Genetic polymorphisms in NOD1 and NOD2 may interact with H. pylori infection and may play important roles in promoting the development of gastric cancer in the Chinese population.

Role of NOD1/CARD4 and NOD2/CARD15 gene polymorphisms in cancer etiology

NOD1/CARD4 and NOD2/CARD15 are members of Nod-like receptor family. They are located in cytosol, bind bacterial and viral ligands and play a key role in realization of innate and adaptive immune response, apoptosis, autophagy, and reactive oxygen species generation. Polymorphisms in NOD1/CARD4 and NOD2/CARD15 genes may shift balance between pro- and anti-inflammatory cytokines, modulating the risk of infection, chronic inflammation and cancer. NOD1/CARD4 and NOD2/CARD15 gene polymorphisms may be associated with altered risk of gastric, colorectal, breast, ovarian, prostate, testicular, lung, laryngeal, liver, gallbladder, biliary tract, pancreatic, small bowel, kidney, urinary bladder cancer, skin cancer, nonthyroid endocrine tumors, lymphoma and leukemia. The short list of such polymorphisms perspective for oncogenomic investigations may include rs2006847, rs2066845, rs2066844, rs2066842, ND(1)+32656, rs2075820 whereas rs104895493, rs104895476, rs104895475, rs104895474, rs104895473, rs104895472, rs104895462, rs104895461, rs104895460, rs104895438, rs5743291, rs5743260, rs2076756, rs2066843, Pro371Thr, Ala794Pro, Gln908His, rs72551113, rs72551107, rs6958571, rs2907749, rs2907748, rs2075822, rs2075819, rs2075818 may be added to the extended list. Reasons of discrepancies between different studies include confounding host genetic, bacterial, or environmental factors modulating penetrance of variant allele and affecting risk of condition increasing cancer risk, different bacterial impact in aetiology of such conditions, differences in sample size, clinicopathological characteristics, diagnostics, stratification, genotyping methods, and chance.

Nod-like receptors in intestinal homeostasis, inflammation, and cancer

NLRs have been shown in a number of models to protect against microbial infection through their ability to participate in "pattern recognition" and their triggering of inflammatory pathways to control infection. Over the past few years, however, the role of NLRs, especially Nod1, Nod2, and NLRP3, in intestinal homeostasis has been highlighted. Indeed, these specific NLRs have been implicated in IBD, in particular, the association of Nod2 with CD, yet a clear understanding of how dysfunctional NLR activation leads to aberrant inflammation is still the focus of much investigation. In this review, we will examine how NLRs participate in the maintenance of gut homeostasis and how upset of this regulation can tip the balance toward chronic inflammation and intestinal cancer.

Association analysis of the NOD2 gene with susceptibility to graft-versus-host disease in a Japanese population

Members of the nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) family participate in the innate immune system, exerting widespread effects on cytokine secretion, autophagy, and apoptosis. Recent studies in Caucasians revealed the association between mutants of NOD2, a member of the NLR family, and severity of acute graft-versus-host disease (GVHD). NOD2 polymorphism screening has been recommended for donor selection and risk assessment at bone marrow transplantation. To investigate whether NOD2 plays a role in the pathogenesis of GVHD in a Japanese population, we examined DNA from 142 bone marrow transplant patient/donor pairs to detect genetic variation in the NOD2 gene. No genetic variants of NOD2 were associated with the severity of acute GVHD in our patients. However, a weak association between a single nucleotide polymorphism in the NOD2 gene (R471C) and acute myeloid leukemia in the bone marrow patients (p = 0.029, odds ratio 4.08, 95% CI 1.22-13.67) was detected. This polymorphism was not prevalent in 479 Crohn's disease (CD) patients in Japan. These results suggest that, in the Japanese population, unlike the Caucasian, NOD2 is not a major contributor to susceptibility to severe acute GVHD.

CARD15 mutations and colorectal cancer in a South European country

PURPOSE

CARD15 mutations are associated with higher susceptibility to Crohn's disease (CD) and longstanding colonic CD increases the risk of developing colorectal cancer (CRC). The relation between these mutations and sporadic CRC remains controversial. The aim of this study was to assess whether germline and/or somatic CARD15 mutations are risk factors for sporadic CRC in Portugal and whether there are genotype-phenotype correlations in these patients.

METHODS

The three main CARD15 mutations (R702W, G908R and 3020insC) were researched in 112 sporadic CRC patients and 152 healthy subjects.

RESULTS

Overall, CARD15 mutations were found in 18 patients (16.1%) and in 15 controls (9.9%; p = 0.132). Individually, the incidence of R702W was significantly higher in patients than in controls (12.5% vs. 5.3%, p = 0.035), whereas the genotype frequencies for G908R (2.7% vs. 3.3%) and 3020insC (0.9% vs. 1.3%) were not statistically different between the two groups. Entire genotypic agreement was found in patients genotyped for blood and neoplastic DNA. A significantly higher incidence of CARD15 mutations was detected in patients with CRC diagnosed under 60 years old (28.6% vs. 10.4%, p = 0.015) and in female patients (24.4% vs. 10.4%, p = 0.048). No associations were found between CARD15 mutations and family history, symptoms or CRC pathologic characteristics.

CONCLUSIONS

The CARD15 R702W variant might be a predisposing factor to sporadic CRC in Portugal, particularly in patients under 60-years old and in female patients. This susceptibility appears to be linked with germline CARD15 mutations. Nevertheless, we have found no evidence that CARD15 mutations predict the pathologic characteristics of CRC.

Association of c.802C>T polymorphism of NOD2/CARD15 gene with the chronic gastritis and predisposition to cancer in H. pylori infected patients

This paper shows analysis of the association of the 802C>T polymorphism of the NOD2/CARD15 gene with the occurrence of the chronic inflammation of the gastric mucosa associated with the Helicobacter pylori infections, development of intestinal metaplasia and dysplasia and, in the result of this, gastric cancer. Genomic DNA samples were extracted from paraffin blocks of gastric mucosal biopsies and from peripheral blood. H. pylori infection was confirmed by histological analysis and urease test. Pyrosequencing of 802C>T polymorphism of the NOD2/CARD15 gene was performed for H. pylori infected patients (131) and population group (100). Analysis of the NOD2/CARD15 gene showed that frequency of the T allele was significantly higher (32.8%) in the group of patients in comparison with the population group (18.1%), with the relative risk of 1.8. In the patient group, the frequency of the CC genotype was 51.1%, CT 32.1% and TT 16.8% (relative risk: 0.7, 1.1 and 4.2, respectively), while in the population group it was 69.0%, 25.7% and 5.3% (relative risk: 1.0, 0.9 and 1.3, respectively). The increasing frequency of the T allele and CT and TT genotypes in the patients with increasingly deeper changes in the gastric mucosa becomes apparent. Our findings suggest that polymorphism 802C>T is associated with changes in gastric mucosa and plays a significant role in the initiation and the progression of carcinogenesis. The number of observed mutations in gastric mucosa correlated with severity of disease.

Differential effects of NOD2 polymorphisms on colorectal cancer risk: a meta-analysis

INTRODUCTION

Since Kurzawski et al. described an association between the 3020insC NOD2 single nucleotide polymorphism and the risk of colorectal cancer(CRC) in 2004, reports published in the past several years have controversial results regarding the relationship between the development of CRC and NOD2 gene polymorphisms. To clarify the potential role of NOD2 P286S, R702W, G908R, and 3020insC polymorphisms in CRC patients, we have undertaken a systematic review and meta-analysis of published articles.

MATERIALS AND METHODS

Studies reporting on NOD2 polymorphisms and CRC were searched in the PubMed, EMBASE, and the Science Citation Index from the inception of each database to May, 2009. The search strategy included the keywords "CRC", "colon cancer", "rectal cancer", "polymorphism", and "NOD2/CARD15".

RESULT

Eight eligible case-control studies about Caucasians from four countries contributed data on 5,888 subjects (cases: 3,524; controls: 2,364). Compared to the wild genotype, the R702W, G908R, and 3020insC polymorphisms were associated with an increased risk of CRC (odds ratio (OR): 1.59, 1.98, 1.44; 95% confidence interval (CI): 1.09-2.32, 1.14-3.44, 1.13-1.84; P = 0.02, 0.01, 0.003). However, P268S polymorphism did not influence CRC risk (OR: 1.27; CI: 0.32-5.00; P = 0.73).

CONCLUSIONS

These findings indicate that NOD2 R702W, G908R, and 3020insC polymorphisms contribute to CRC susceptibility in Caucasians. Meta-analysis of these polymorphisms in NOD2 gene will help determine their role in CRC carcinogenesis.

NOD2/CARD15 genotype and common gastrointestinal diseases in 43,600 individuals

OBJECTIVES

NOD2/CARD15 is involved in the innate immune response and three polymorphisms in this gene (Arg702Trp rs2066844, Gly908Arg rs2066845 and Leu1007fsinsC rs5743293) have been associated with risk of the rare Crohn's disease. We tested the hypothesis that polymorphisms in NOD2/CARD15 associate with risk of nine common gastrointestinal diseases.

DESIGN AND SETTING

We genotyped 43 596 white individuals from the Danish general population followed for 31 years, during which time 782 developed oesophagitis and reflux, 1395 ulcus ventriculi and duodeni, 1384 gastritis and dyspepsia, 1407 appendicitis, 646 irritable bowel syndrome, 1301 infectious diseases of the gastrointestinal tract, 681 anal fissure, fistula and abscess, 826 gastrointestinal cancer and 161 developed cancer in liver and pancreas.

RESULTS

Some 89% were non-carriers, 11% heterozygotes, 0.15% homozygotes and 0.23% compound heterozygotes. Cumulative incidences differed by genotype for appendicitis (log-rank P = 0.02), anal fissure, fistula and abscess (P = 0.003) and gastrointestinal cancer (P = 0.004), but not for any of the other endpoints. Compared with non-carriers, age and sex adjusted hazard ratios were 2.7 (95%CI 1.4-5.5) for appendicitis amongst compound heterozygotes, 3.2 (1.3-7.8) for anal fissure, fistula and abscess amongst compound heterozygotes, and 3.8 (1.6-9.2) for gastrointestinal cancer amongst homozygotes, whilst other genotypes did not have increased risk. The increased risk of gastrointestinal cancer amongst homozygotes appeared to be similar amongst both men and women and amongst those below or above 60 years, and likely included both upper gastrointestinal cancer and colorectal cancer.

CONCLUSIONS

NOD2/CARD15 polymorphisms are not major risk factors for common gastrointestinal diseases; however, we cannot completely exclude association with appendicitis, anal fissure, fistula and abscess, and gastrointestinal cancer.

Pathogen recognition receptors, cancer and inflammation in the gut

The pathogen recognition receptors (PRRs) initiate immediate responses against infection and tissue damage to protect the host from microbial invasion. In response to mucosal damage, intestinal PRR signaling initiates damage repair processes. Recent advances appear to link PRR abnormalities and inflammatory as well as neoplastic intestinal disorders. Emerging evidence suggests a dual role of PRRs, in which they may simultaneously induce tumorigenesis and antitumor immunity. PRR may induce tumor cell proliferation by activating cell survival signaling mainly via NF-kappaB, but this signal can activate dendritic cells to promote antitumor immunity. TLR signaling within the tumor cells may result in evasion of immune surveillance, propagation of metastatic growth, or rather, induction of tumor cell apoptosis depending on ligands. Epithelial cells induce endogenous PRR ligands when damaged or during neoplastic transformation. Targeted manipulation of PRR signaling may provide emerging opportunities for the development of new therapeutic strategies for many gastrointestinal diseases.

Towards a molecular risk map--recent advances on the etiology of inflammatory bowel disease

Recent advances have enabled a comprehensive understanding of the genetic architecture of inflammatory bowel disease (IBD) with over 30 identified and replicated disease loci. The pathophysiological consequences of disease gene variants in Crohn disease and ulcerative colitis, the two main subentities of IBD, so far are only understood on the single disease gene level, yet complex network analyses linking the individual risk factors into a molecular risk map are still missing. In this review, we will focus on recent pathways and cellular functions that emerged from the genetic studies (e.g. innate immunity, autophagy) and delineate the existence of shared (e.g. IL23R, IL12B) and unique (e.g. NOD2 for CD) risk factors for the disease subtypes. Ultimately, the defined molecular profiles may identify individuals at risk early in life and may serve as a guidance to administer personalized interventions for causative therapies and/or early targeted prevention strategies. Due to this comparatively advanced level of molecular understanding in the field, IBD may represent precedent also for future developments of individualized genetic medicine in other polygenic disorders in general.

NOD-like receptors--pivotal guardians of the immunological integrity of barrier organs

NOD-like receptors (NLRs) exert pivotal roles in innate immunity as sensors of exogenous or endogenous cellular danger signals. The NLR protein family has a characteristic domain architecture comprising a central nucleotide binding and oligomerization domain (NOD), an N-terminal effector binding domain and C-terminal leucine-rich repeats (LRRs). Mutations in NLR genes are genetically associated with a number of chronic inflammatory diseases of barrier organs. In this chapter, we focus on the influence of NLR regulation and function in the complex pathophysiology of mucosal homeostasis. The understanding of NLR biology may guide our future understanding of how the interaction between the human genome and the metagenome of transient and resident microbiota precipitates into chronic inflammatory disorders, such as Crohn's disease or atopy.

Investigation of innate immunity genes CARD4, CARD8 and CARD15 as germline susceptibility factors for colorectal cancer

Background

Variation in genes involved in the innate immune response may play a role in the predisposition to colorectal cancer (CRC). Several polymorphisms of the CARD15 gene (caspase activating recruitment domain, member 15) have been reported to be associated with an increased susceptibility to Crohn disease. Since the CARD15 gene product and other CARD proteins function in innate immunity, we investigated the impact of germline variation at the CARD4, CARD8 and CARD15 loci on the risk for sporadic CRC, using a large patient sample from Northern Germany.

Methods

A total of 1044 patients who had been operated with sporadic colorectal carcinoma (median age at diagnosis: 59 years) were recruited and compared to 724 sex-matched, population-based control individuals (median age: 68 years). Genetic investigation was carried out following both a coding SNP and haplotype tagging approach. Subgroup analyses for N = 143 patients with early manifestation of CRC (≤50 age at diagnosis) were performed for all CARD loci and subgroup analyses for diverse age strata were carried out for CARD15 mutations R702W, G908R and L1007fs. In addition, all SNPs were tested for association with disease presentation and family history of CRC.

Results

No significant differences were observed between the patient and control allelic or haplotypic spectra of the three genes under study for the total cohort (N = 1044 patients). None of the analysed SNPs was significantly associated with either tumour location or yielded significant association in the familial or non-familial CRC patient subgroups. However, in a patient subgroup (≤45 age at diagnosis) with early disease manifestation the mutant allele of CARD15 R702W was found to be significantly associated with disease susceptibility (9.7% in cases vs 4.6% in controls; P_allelic = 0.008, P_genotypic = 0.0008, OR_allelic = 2.22 (1.21-4.05) OR_ressessive = 21.9 (1.96-245.4).

Conclusion

Variation in the innate immunity genes CARD4, CARD8 and CARD15 is unlikely to play a major role in the susceptibility to CRC in the German population. But, we report a significant disease contribution of CARD15 for CRC patients with very early disease manifestation, mainly driven by variant R702W.

Clinical characteristics of tumors derived from colorectal cancer patients who harbor the tumor necrosis factor alpha-1031T/T and NOD2 3020insC polymorphism

BACKGROUND

Genetic predispositions to disease have focused on highly penetrant causative changes in tumor suppressor genes or genes associated with DNA mismatch repair. New investigations are revealing new genetic associations with disease that are more subtle in their association with disease and require characterization.

METHODS

In this report we have examined the tumor characteristics in a group of patients who have been shown to harbor two polymorphisms in two genes that are associated with the immune system NOD2 and TNFalpha.

RESULTS

Colorectal cancers from patients with NOD2 3020insC and TNFalpha-1031T/T constitutional changes are mostly right-sided disease (OR=2.21, p=0.03) with a tendency to higher stages (OR=2.41, p=0.06), increased number of associated polyps (OR=1.77, p=0.16) and later age of average age of disease onset (p=0.039).

CONCLUSION

The results reveal that there appear to be specific characteristics associated with the tumors that may aid in determining management strategies to reduce the risk of disease.

NOD2/CARD15 polymorphisms impair innate immunity and increase susceptibility to gastric cancer in an Italian population

In the present case-control study we investigated the potential role of CARD15 R702W, G908R, and 1007fs polymorphisms in Italian gastric cancer patients. The study population consisted of 170 gastric cancer patients and 156 controls. Unconditional regression (odds ratios and 95% confidence interval) was used to investigate the association of the studied polymorphisms with gastric cancer. Higher allele frequencies of R702W and 1007fs polymorphisms were observed in patients with gastric cancer compared with controls (8.53 vs 2.3 and 9.4 vs 0.7, respectively). CARD15 R702W and 1007fs polymorphisms were significantly correlated with gastric cancer incidence (p < 0.0001, p < 0.0001, respectively). No correlation was found upon analyzing the G908R single nucleotide polymorphism (SNP). Our study reports an increased susceptibility to gastric cancer in Italian populations when R702W and 1007fs polymorphisms in the coding region of CARD15 are present. The interaction between NOD-induced proinflammatory cytokines on gastric mucosa and environmental carcinogens could represent one of the mechanisms by which CARD15 polymorphisms increase the susceptibility to gastric cancer. Meta-analyses of these SNPs and further analyses of additional polymorphisms/haplotypes in NOD genes will help determine their role in carcinogenesis.

Inflammatory response gene polymorphisms and their relationship with colorectal cancer risk

Backgroud

Patients with chronic inflammatory bowel disease (IBD) are at an increased risk of colorectal cancer (CRC) and it is estimated that one in six persons diagnosed with IBD will develop CRC. This fact suggests that genetic variations in inflammatory response genes may act as CRC disease risk modifiers.

Methods

In order to test this hypothesis we investigated a series of polymorphisms in 6 genes (NOD2, DLG5, OCTN1, OCTN2, IL4, TNFα) associated with the inflammatory response on a group of 607 consecutive newly diagnosed colorectal cancer patients and compared the results to controls (350 consecutive newborns and 607 age, sex and geographically matched controls).

Results

Of the six genes only one polymorphism in TNFα(-1031T/T) showed any tendency to be associated with disease risk (64.9% for controls and 71.4% for CRC) which we further characterized on a larger cohort of CRC patients and found a more profound relationship between the TNFα -1031T/T genotype and disease (64.5% for controls vs 74.7% for CRC cases above 70 yrs). Then, we investigated this result and identified a suggestive tendency, linking the TNFα -1031T/T genotype and a previously identified change in the CARD15/NOD2 gene (OR = 1.87; p = 0,02 for CRC cases above 60 yrs).

Conclusion

The association of polymorphisms in genes involved in the inflammatory response and CRC onset suggest that there are genetic changes capable of influencing disease risk in older persons.

Review: variability of host-pathogen interaction

The course of every infection is different. The same pathogen can lead to subclinical, mild, severe or lethal infections in individuals. But is this just chance or determined by individual differences--on the side of the host as well as on the side of the pathogen? If so, we might need to consider these variations for treatment decisions. Indeed, we now understand that genetic polymorphisms and health status represent inborn and acquired risk factors. Similarly, pathogens impress with an increasing number of already identified virulence factors and host response modifiers. The emerging, more complex, view of the factors determining course and outcome of infections promises to enable more tailored and thus, hopefully, more effective treatment decisions.

The Nodosome: Nod1 and Nod2 control bacterial infections and inflammation

Toll-like receptors (TLRs) and the nucleotide-binding domain, leucine rich repeat containing family (or Nod-like receptors, NLRs) are two important families of microbial sensors that are membrane-associated and cytosolic molecules, respectively. The Nod proteins Nod1 and Nod2 are two NLR family members that trigger immune defense in response to bacterial peptidoglycan. Nod proteins fight off bacterial infections by stimulating proinflammatory signaling and cytokine networks and by inducing antimicrobial effectors, such as nitric oxide and antimicrobial peptides. Nod1 is also critically implicated in shaping adaptive immune responses towards bacterial-derived constituents. In addition, recent evidence has demonstrated that mutations in Nod1 and Nod2 are associated with a number of human inflammatory disorders, including Crohn's disease, Blau syndrome, early-onset sarcoidosis, and atopic diseases. Together, Nod1 and Nod2 represent central players in the control of immune responses to bacterial infections and inflammation.

No evidence for association of NOD2 R702W and G908R with colorectal cancer

Polymorphisms in nucleotide oligomerization domain 2 gene (NOD2) have been associated with increased susceptibility to Crohn's disease. Recently, possible association of the NOD2 variants R702W, G908R and 3020insC with colorectal cancer (CRC) has been studied among Polish, Greek, Finnish and New Zealand Caucasian CRC patients, but the results have been controversial. In the Polish study, 3020insC alone, and in the Greek study all the 3 variants, showed association with CRC. In a study from New Zealand, R702W appeared to increase CRC risk. In addition, the combined frequencies of the 3 variants were significantly elevated in CRC patients compared with healthy controls. We have previously shown that NOD2 3020insC is not associated with increased CRC risk in Finland. In the current study, we have genotyped the R702W and G908R in a population-based series of 1,042 CRC patients and in 508 healthy controls to study the possible contribution of these variants to CRC predisposition. Of the CRC patients, 953 were successfully analyzed. R702W and G908R were equally, frequently seen in CRC patients and controls (R702W: 2.2% vs. 2.1%; G908R: 0.3% vs. 0.2%). No associations between NOD2 variants and clinical characteristics were observed. Our results indicate that NOD2 variants R702W, G908R and 3020insC do not predispose to CRC in Finland. Environmental or additional genetic factors may play a role in CRC development in NOD2 variant carriers. Further work is necessary to establish the possible role of NOD2 variants in CRC predisposition.

Prospective study of interaction between alcohol, NSAID use and polymorphisms in genes involved in the inflammatory response in relation to risk of colorectal cancer

Inflammatory bowl disease predisposes to cancer of the colorectum, and the use of non-steroidal anti-inflammatory drugs (NSAIDs) decreases the risk; hence genetic variations that modify the inflammatory response may alter the risk of colorectal cancer (CRC). The purpose of this study was to determine if polymorphisms associated with an altered inflammatory response are associated with colorectal cancer risk, and to investigate the possible interaction with lifestyle factors such as alcohol use, smoking and NSAID use. We studied 355 adenocarcinoma cases and 753 control persons, nested within the prospective "Diet, Cancer and Health" study. None of the polymorphisms were associated with risk of colorectal cancer. A statistically significant interaction between PPARgamma2 Pro(12)Ala and alcohol was found, where alcohol use was associated with a 22% increased risk of CRC per 10g alcohol/day among carriers of the variant allele but not among homozygous wild type allele carriers (P for interaction=0.02). Moreover, an interaction between DLG5 R30Q and NSAID use was found (P for interaction=0.02). Our results do not suggest that inborn variations in the inflammatory response play any major role in risk of colorectal cancer.

Common NOD2/CARD15 variants are not associated with susceptibility or the clinicopathologic characteristics of sporadic colorectal cancer in Hungarian patients

BACKGROUND

Epidemiological observations suggest that cancer arises from chronically inflamed tissues. Inflammatory bowel disease (IBD) is a typical example as patients with longstanding IBD are at an increased risk for developing colorectal cancer (CRC) and mutations of the NOD2/CARD15 gene increase the risk for Crohn's disease (CD). Recently, NOD2/CARD15 has been associated with a risk for CRC in some studies, which stemmed from ethnically diverse populations. Our aim was to identify common NOD2/CARD15 mutations in Hungarian patients with sporadic CRC.

METHODS

A total of 194 sporadic CRC patients (m/f: 108/86, age at diagnosis of CRC: 63.2 +/- 9.1 years old) and 200 healthy subjects were included. DNA was screened for SNP8, SNP12 and SNP13 NOD2/CARD15 mutations by denaturing-HPLC and confirmed by direct sequencing.

RESULTS

NOD2/CARD15 mutations were found in 28 patients (14.4%) and in 23 controls (11.5%, p = NS). Allele frequencies for SNP8/R702W (1.8% vs. 1.5%) SNP12/G908R (1.8% vs. 1.8%) and SNP13/3020insC (3.6% vs. 2.5%) were also not statistically different between patients and controls. The clinicopathologic characteristics of CRC patients with or without NOD2/CARD15 mutations were not significantly different.

CONCLUSION

Our results suggest that common NOD2/CARD15 mutations alone do not contribute to CRC risk in the Hungarian population.

NOD2/CARD15 disease associations other than Crohn's disease

At this moment, few confirmed associations between NOD2 mutations and diseases other than Crohn's disease (CD) and Blau syndrome (BS) have been reported, but research is ongoing in several fields where a genetic susceptibility factor and/or a role for the innate immune system is suspected. Whether the Crohn's-associated CARD15 mutations lead to a loss or gain of function of the NOD2 receptor is subject to controversy, and by which mechanisms this change in function might increase the susceptibility to CD is still under investigation. The possible involvement of NOD2/CARD15 in the pathogenesis of certain diseases with already (partially) unraveled pathophysiologic mechanisms might contribute to our further understanding of NOD2/CARD15 and its function in CD. We review studies on the association of CARD15 variants with diseases other than CD. The association of NOD2/CARD15 mutations with CD and BS, and possibly also early onset sarcoidosis, suggests a role for the gene in the development of granulomata and granulomatous diseases, possibly by inappropriate activation of the immune system. The data from the oncology field suggest that this inappropriate activation might even lead to uncontrolled proliferation of certain cell types. The studies in allergic diseases and atopy are the largest so far, and the association of NOD2/CARDI5 mutations with atopic phenotypes might be an indication that CARD15 also plays a role in the Th2 pathway. Finally, transplantation studies indicate that the genetic background of a patient should be taken into account when considering hematopoietic stem cell transplantation, given the increased risk of mortality and graft versus host disease observed. Whether NOD2 variants are also associated with an increased risk for infections and sepsis in patients receiving immunosuppressive therapies is unclear.

NOD-like receptors and human diseases

NOD-like receptors are cytosolic proteins that contain a central nucleotide-binding oligomerization domain (NACHT), an N-terminal effector-binding domain and C-terminal leucine-rich repeats (LRRs). NOD-like receptors have been implicated as ancient cellular sentinels mediating protective immune responses against intracellular pathogens. Recent studies have described the genetic association of polymorphisms in NOD-like receptor genes with complex chronic inflammatory barrier diseases, such as Crohn's disease and asthma and with rare auto-inflammatory syndromes including familial cold urticaria, Muckle-Wells syndrome and Blau syndrome. Whereas genetic variability in NLRs may have been an important element to provide plasticity to antigen recognition and host defense in the past, recent changes in the lifestyle of industrialized societies (e.g. hygiene ("cold-chain-hypothesis"), nutrition, or antibiotics) may have turned ancient genetic variability into disease-causing mutations. The review focuses on NLR function in the molecular pathophysiology of human inflammatory disorders.

Prevalence of the NOD2 3020insC mutation in aggregations of breast and lung cancer

Both breast and lung cancers are common malignancies and within the context of known genetic predispositions to breast cancer, no association has been made in linking the two diseases together. This does not exclude the possibility that such associations may exist that lie outside the known high-risk breast cancer families. To examine the likelihood of common genetic factors that could influence the risk of disease, two sets of consecutively collected tumor groups were examined for the 3020insC mutation in the NOD2/CARD15 gene. A total of 4107 consecutively collected breast cancer patients were assessed for the prevalence of the 3020insC mutation and compared to a consecutively collected series of 389 lung cancer patients and 2068 control samples. The results revealed that a proportion of breast cancer patients who had a first or a second degree relative diagnosed with lung cancer were more likely to harbour a change in NOD2/CARD15 compared to patients who had no relatives affected by lung cancer. Furthermore, this difference appeared to be specific to the breast and lung cancer subgroup since there was no difference in the frequency of the 3020insC allele in the consecutively collected lung cancer patients. In conclusion, it appears that the 3020insC mutation of the NOD2/CARD15 gene may be a genetic predisposing factor for aggregations of breast and lung cancer.

Influence of polymorphisms in the NOD1/CARD4 and NOD2/CARD15 genes on the clinical outcome of Helicobacter pylori infection

Host immune response influences the clinical outcome of Helicobacter pylori infection leading to ulcer disease, gastric carcinoma and mucosa-associated lymphoid tissue (MALT) lymphoma. A genetic risk profile for gastric cancer has been identified, but genetic susceptibility to develop MALT lymphoma is still unclear. We investigated the role of NOD1 and NOD2 as intracellular recognition molecules for pathogen-associated molecules in H. pylori infection in vitro and analysed the influence of single nucleotide polymorphisms on susceptibility to ulcer disease and MALT lymphoma. Expression of NOD1 and NOD2 significantly sensitized HEK293 cells to H. pylori-induced NF-kappaB activation in a cag pathogenicity island (cagPAI)-dependent manner. In cells carrying the Crohn-associated NOD2 variant R702W the NF-kappaB response was significantly diminished. NOD1/NOD2 expression levels were induced in the gastric epithelium in H. pylori-positive patients. No mutations were found to be associated with gastritis or gastric ulcer development. However, the R702W mutation in the NOD2/CARD15 gene was significantly associated with gastric lymphoma. Carrier of the rare allele T had a more than doubled risk to develop lymphoma than controls [odds ratio (OR): 2.4, 95% confidence interval (CI): 1.2-4.6; P < 0.044]. H. pylori-induced upregulation of NOD1 and NOD2 in vivo may play a critical role in the recognition of this common pathogen. A missense mutation in the leucine-rich region of CARD15 is associated with gastric lymphoma.

Caspase recruitment domain-containing protein 15 mutations in patients with colorectal cancer

The caspase recruitment domain-containing protein 15 (CARD15) plays a crucial role in mediating the innate immune response. Mutations within this protein have been shown to be independent risk factors for the development of Crohn's disease in Caucasians. As Crohn's disease patients are at increased risk of developing sporadic colorectal cancer, it is conceivable that genetic variability within CARD15 may also play a role in determining susceptibility to this gastrointestinal malignancy in individuals without Crohn's disease. This hypothesis is supported by the findings of two case-control studies that found the frequencies of CARD15 mutations were significantly elevated in Polish and Greek colorectal cancer patients. Given the results of these previous studies, we examined whether the high incidence of sporadic colorectal cancer observed in New Zealand Caucasians was due to mutations within CARD15. To answer this question, we genotyped 133 colorectal cancer patients and 201 Caucasian controls for R702W, G908R, 1007fs, and P268S. Chi(2) Testing found that the combined frequency of R702W, G908R, and 1007fs was significantly elevated in colorectal cancer patients compared with controls (P = 0.001; odds ratio, 2.8; 95% confidence interval, 1.5-5.4), but no association was detected between tumor behavior or age of disease onset and CARD15 mutations in our colorectal cancer cohort. This study is the first to explore the link between CARD15 mutations and colorectal cancer in New Zealand Caucasians. Our results strongly suggest that CARD15 influences susceptibility to colorectal cancer, but we have found no evidence to indicate that CARD15 mutations predict the clinicopathologic characteristics of this disease.

The 3020insC Allele of NOD2 Predisposes to Cancers of Multiple Organs

The NOD2 gene has been associated with susceptibility to Crohn's disease and individuals with Crohn's disease are at increased risk for cancer at a number of organ sites. We studied the association between the 3020insC allele of the NOD2 gene and cancer among 2604 cancer patients and 1910 controls from Poland. Patients were diagnosed with one of twelve types of cancer in the Szczecin region between 1994 and 2004. Significant associations were found for colon cancer (OR = 1.8; 95% CI 1.2 to 2.6), for lung cancer (OR = 1.7; 95% CI = 1.1 to 2.5) and for ovarian cancer (OR = 1.6; 95% CI 1.1 to 2.3). In addition, a significant association was found for early-onset laryngeal cancer (OR = 2.9; 95% CI 1.4 to 6.2) and for breast cancer in the presence of DCIS (OR = 2.1 95% CI = 1.2 to 3.6). The NOD2 3020insC allele is relatively common (in Poland 7.3% of individuals) and may be responsible for an important fraction of cancer cases. We estimate that the lifetime cancer risk among carriers of this allele is 30% higher than that of individuals with two wild-type alleles.