Positive link between variant Toll-like receptor 4 (Asp299Gly and Thr399Ile) and colorectal cancer patients with advanced stage and lymph node metastasis.

Toll-like receptors (TLRs) are considered as major endotoxin-signaling receptor and as crucial sensors of innate immunity. TLRs recognize pathogen-associated molecular patterns; induce effectors genes involving inflammatory cytokines and therefore initiation of adaptative immune responses against pathogens. Recently, it has been shown that TLRs are involved in tumor progression. In fact, increased level of TLR4 is associated with progression of colon malignancies. Even, TLR4 polymorphism has been shown associated with susceptibility to have colorectal cancer. Our study aimed to investigate an association between TLR4 Asp299Gly (D299G) and Thr399Ile (T399I) polymorphisms in Tunisian patients with colorectal cancer. Using a primer extension method (SNaPshot), we genotyped two variants of TLR4 D299G and T399I in 100 patients with colorectal cancer and 140 healthy controls in Tunisian population. Interesting, we noted a significant association between T399I polymorphism and tumor differentiation (p = 0.027) and tumor architecture (p = 0.02) in colorectal cancer (CRC) patients. We also showed a significant association of D299G with an increased risk of advanced stage (p = 0.03). Finally, we observed a positive link between D299G and T399I polymorphisms and CRC patients with lymph node (p = 0.00024; p = 0.0005, respectively) and metastasis (p = 0.001; p = 0.002, respectively). However, we found no evidence to support a significant association between TLR4 D299G and T399I polymorphisms and colorectal cancer susceptibility. Our findings suggest that TLR4 D299G and T399I polymorphisms are significantly associated with clinical features variables. TLR4 polymorphisms may serve as biomarker of disease progression. Therefore, our results need confirmation in even larger studies.

Significant association between interleukin-17A polymorphism and colorectal cancer.

Interleukin (IL) 17A is an inflammatory cytokine expressed by Th 17 cells and plays a role in tissue inflammation by inducing release of proinflammatory and neutrophil-mobilizing cytokines. We have investigated the association between colorectal cancer and polymorphisms of IL17A (rs2275913. G197A). The study was performed in 241 subjects (102 with colorectal cancer and 139 healthy controls). Genotypes were determined by fluorescent-based restriction fragment length polymorphism method. The association between the molecular features at the gene in relation to tumor and patient clinical characteristics was analyzed. There was a significant difference between the genotype frequencies of IL17A G197A of control subjects (GG 68.34 % and GA + AA 31.65 %) and patients with colorectal cancer (GG 47.05 % and GA + AA 52.94 %) (p = 0.001 with odds ratio (OR) 2.45 (1.43-4.11)). IL17A G197A polymorphism is particularly associated with colon cancer. Indeed, the IL17A GG genotype could be considered as a protective factor against colon cancer (p = 0.00001) with OR 3.77 (2.04-6.99). We have noted a significant association of IL17A G197A polymorphism not only with tumor localization (p = 0.003) but also with tumor differentiation (p = 0.0005) in CRC patients. We have also showed a significant association of G197A variant with an increased risk of advanced stage (p = 0.005). Our result suggests that the A allele of IL17A gene is involved in susceptibility to colorectal cancer and is associated with clinical features as tumor location, tumor differentiation, and TNM stage. IL17A polymorphism may serve as biomarker of disease location and progression.

Involvement of IL17A, IL17F and IL23R Polymorphisms in Colorectal Cancer Therapy.

IL23/IL17 pathway plays an important role in the development of inflammatory bowel diseases (IBD). In general, the genes encoding the cytokines are genetically polymorphic and polymorphisms in genes IL23R and IL17 have been proved to be associated with its susceptibility to inflammatory diseases as well as cancer including colorectal cancer. Moreover, it has been shown that these interleukins are involved in anti-tumor or pro-tumor effects of various cancers. Previously, we showed that there is a significant association between IL17A, IL17F and IL23R polymorphisms as well as the occurrence of colorectal cancer and the clinical features of the disease. The purpose of the present work is to investigate an association between IL17A, IL17F and IL23R polymorphisms in 102 Tunisian patients with colorectal cancer treatment. The association was analyzed by statistical tools. We found that patients with mutated genotypes of IL17A G197A SNP could be a risk factor for the inefficiency of chemotherapy and radiotherapy. Unlike IL17F variant, patients with wild type genotypes require surgery and adjuvant chemotherapy. On the one hand, we found no evidence that supports a significant association between IL23R polymorphism and the combined genotypes of these three genes and the colorectal cancer treatment. On the other hand, we showed that there is an important interaction between IL17A/IL17F polymorphisms and the stage of the disease as well as its treatment. Finally, patients with IL17F wild type genotype highlighted that there is a valid longer OS without all treatments and with radiotherapy and a neoadjuvant chemotherapy. In contrast, we observed that there are no relationships between IL17A, IL23R and the survival of these patients neither with nor without the treatment. Our results suggest that polymorphisms in IL17A and IL17F genes may be a predictive source of colorectal cancer therapy type. Therefore, IL17F may serve as an independent prognostic factor for overall survival in patients with colorectal cancer.

Significant association between IL23R and IL17F polymorphisms and clinical features of colorectal cancer.

Th17cells are involved in inflammatory and autoimmune diseases. These cells may be involved in pathological processes mainly producing pro-inflammatory cytokines. Recently, it was shown that the IL23/IL17 pathway plays an important role in the development of inflammatory bowel disease. In general, genes encoding cytokines are genetically polymorphic and polymorphisms in genes IL23R el IL17F were shown associated with susceptibility to Crohn's disease and ulcerative colitis which in their turn are considered as risk factors for developing colorectal cancer (CRC). Our approach is to study IL17F and IL23R polymorphisms as risk factor associated with CRC in the Tunisian population in patients and healthy controls. Interesting, we noted a significant association between IL17F and IL23R polymorphisms and tumor location (p=0.0001 and p=0.049, respectively), tumor histology (p=0.007 and p=0.049, respectively) and tumor architecture (p=0.0000000001 and p=0.07, respectively) in CRC patients. We also showed a significant association of IL17F variant with an increased risk of TNM stage III/IV (p=0.007), showing an increased risk of advanced stage. Finally, we observed a positive link between IL17F polymorphism and CRC patients with lymph nodes (p=0.0000000001) and metastasis (p=0.00000009). However, we found no evidence to support a significant association between IL17F and IL23R polymorphisms and colorectal cancer susceptibility. Our findings suggest that IL17F and IL23R polymorphisms were significantly associated with clinical features variables. The IL17F cytokine appear to be involved in the control of tumor growth and invasion of gastrointestinal tumors. IL17 and IL23 polymorphisms or those of their receptors as important determinants of susceptibility to colorectal cancer are still subject to questioning.

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.