Significant association of MCP1 rs1024611 and CCR2 rs1799864 polymorphisms with colorectal cancer and liver metastases susceptibility and aggressiveness: A case-control study.

BACKGROUND: The MCP-1/CCR2 axis is one of the major chemokine signaling pathways that play a crucial role in the tumor microenvironment and has been involved in triggering various tumor progression mechanisms, such as increasing the immunosuppressive cells recruitment and promoting tumor cell proliferation and invasiveness. AIM: The current study investigated the association of MCP1 (rs1024611) and CCR2 (rs1799864) genes variants with the risk as well as prognosis of colorectal cancer (CRC) and colorectal liver metastases (CRLM). SUBJECTS AND METHODS: A retrospective cohort study involved 408 patients (284 CRC and 124 CRLM), and 284 healthy control was conducted. Genotyping of selected polymorphisms was performed by PCR-RFLP assays and confirmed by microchip and capillary electrophoresis. RESULTS: The results highlighted a positive association between MCP1 rs1024611 (non-AA) and CCR2 rs1799864 (GA) genotypes with increased CRC and CRLM risk. Correlation between SNPs and clinicopathological characteristics revealed a positive association between MCP1 rs1024611 and CCR2 rs1799864 (dominant model) and CRC poor prognosis features. Kaplan-Meier survival analysis revealed a significant association between MCP1 rs1024611 non-AA carriers and decreased survival rate. Neoadjuvant treatment showed an improvement in CRC and CRLM survival rates among carriers of MCP1 and CCR2 wild-type genotype. FOLFIRI chemotherapy exhibits reduced survival rates for patients who carried mutated genotypes of MCP1 and CCR2 polymorphisms. CONCLUSION: Considering our results, we suggest That both MCP1 and CCR2 polymorphisms may constitute independent factors for CRC and CRLM occurrence and can be helpful targets for an efficient therapeutic approach.

Clinicopathological characteristics and mutational profile of KRAS and NRAS in Tunisian patients with sporadic colorectal cancer

Background/aim: Colorectal cancer (CRC) is a major public health problem worldwide and in Tunisia due to its increasing rate of incidence. KRAS and NRAS mutations have become a pivotal part of CRC diagnosis, given their association to treatment resistance with antiepidermal growth factor receptor (EGFR) monoclonal antibodies. In this study, we aimed to screen for mutations in KRAS and NRAS genes in Tunisian patients with CRC and explore their correlations with clinicopathological features. Materials and methods: AmoyDx KRAS and NRAS mutation real-time PCR kits were used to screen for mutations in KRAS (exon 2) and NRAS (exons 2, 3, and 4) in 96 CRC tumors. Results: KRAS exon 2 mutations were found in 41.7% (40/96) of the patients. Codon 12's most abundant mutations were G12D and G12V, followed by G12A, while G13D is the predominant mutation in codon 13. KRAS exon 2 mutations were associated with older patients (P = 0.029), left-sided tumors (P = 0.037), and greater differentiation (P = 0.044). The prevalence rate of NRAS mutations was 7.3%, mostly in exon 2. These mutations were associated with early stages of the disease (P = 0.039) and the absence of lymph node metastasis (P = 0.045). Conclusion: It can be inferred from this study that Tunisian CRC patients have a similar frequency of KRAS and NRAS mutations compared to those observed in other populations. Consequently, screening for KRAS and NRAS mutations is crucial for the orientation of therapies and the selection of appropriate candidates, while also helping to avoid unnecessary toxicity and increased costs for patients.

MUC1 and MUC5AC implication in Tunisian colorectal cancer patients

Background/aim: Mucins, such as MUC1 and MUC5AC, are known for their protective and moisturizing role in intestinal epithelium. Their expression is tightly controlled given their essential role in normal tissue homeostasis, whereas their deregulation leads to chronic inflammation, and even cancer. This study aimed to assess the expression profiles of MUC1 and MUC5AC and their implications in colorectal carcinogenesis. Materials and methods: A retrospective study of 202 patients who underwent colorectal cancer (CRC) surgery was conducted. The expression of MUC1 and MUC5AC was investigated by immunohistochemistry and reverse-transcription polymerase chain reaction (RT-PCR). Statistical analysis of mucin expression pattern, as well as the clinicopathological criteria of the patients, was performed using the chi-square test, survival curves were plotted using the Kaplan­Meier product-limit method, and differences between the survival curves were tested using the log-rank test. Results: The expression of both mucins was abnormally high in the tumor tissues for both mRNA and protein. MUC1 expression was correlated with advanced cancer stages and lymph node metastases for both the mRNA (P < 0.016 and P < 0.002, respectively) and protein level (P < 0.006 and P < 0.001, respectively). However, MUC5AC expression did not pinpoint any significant association between the clinicopathological criteria, but patients who expressed MUC5AC showed an increase in overall survival (P < 0.009). Conclusion: The expression of MUC1 might be a poor prognostic biomarker in CRC and could play a role in tumor transformation and metastasis. However, MUC5AC expression might be a good prognostic in the Tunisian cohort.

Stromal cell derived factor-1 and CXCR4 expression in colorectal cancer promote liver metastasis.

BACKGROUND: Recent studies suggest that SDF-1 and CXCR4 are expressed in certain cancer cells, and malignant cells use this chemokine/receptor system to promote tumor progression and metastasis. However, the pathophysiological significance of their expression in colorectal cancer (CRC) tissue has not been fully elucidated. OBJECTIVE: The purpose of this study was to assess SDF-1/CXCR4 expression and to explore its contribution to colorectal cancer. METHODS: We examined SDF-1 and CXCR4 mRNA expression in 124 primary colorectal tumour and 35 liver metastases tissues and matched adjacent noncancerous tissues by reverse transcriptase PCR (RT-PCR). Furthermore, their expression was analyzed by immunohistochemistry. The relationship between SDF-1/CXCR4 expression and clinicopathological features were analyzed by appropriate statistics. X2 test and Kaplan-Meier analysis were used to investigate the correlation between the ligand-receptor expression and prognosis of colorectal cancer patients. RESULTS: The relative mRNA expression of SDF-1 and CXCR4 was significantly elevated in colorectal cancer tissues as compared with adjacent noncancerous tissues (P < 0.001). The high expression of proteins expression in colorectal cancer tissues was significantly correlated with tumor grade (P = 0.0001), clinical stage (P < 0.05), and lymphatic invasion (P < 0.05). Furthermore, patients with CXCR4 nuclear-type expression showed more frequent lymph node metastasis (p = 0.021), advanced clinical stage (p = 0.001) and lymphatic invasion (p = 0.03) than those with cytoplasm staining-type. Kaplan-Meier survival analysis revealed that high expression of the couple SDF-1/CXCR4 correlated with poor prognosis of colorectal cancer patients (P < 0.001). CONCLUSION: SDF-1 and CXCR4 may play an important role in the progression of colorectal cancer. The present data suggest that there is a significant association between SDF-1/CXCR4 to enhance the liver metastases causing poor prognosis. Those proteins may potentially be used as an independent biomarker for the prognostic evaluation of colon cancer in the Tunisian cohort.

Relationship between SDF-1G801A polymorphism and its expression in Tunisian patients with colorectal cancer.

The aim was to evaluate the relationship between SDF-1G801A polymorphism and its immunohistochemical expression in colorectal cancer tissues in the Tunisian cohort. The molecular and immunohistochemical analysis showed that SDF-1G801A polymorphic variant was higher in CRC patients with TNM stage II and III, the SDF-1 expression was significantly increased from normal mucosa to primary tumor (p < 0.05). CRC patients have higher frequency of A allele (52.01%) than controls (26.8%) (P = 0.0001). Thus, SDF-1 polymorphism is a risk factor of colorectal cancer susceptibility in our population, the polymorph genotype of SDF-1 maybe associated with clinical manifestations in CRC patients in Tunisia.

Biological significance of promoter hypermethylation of p14/ARF gene: relationships to p53 mutational status in Tunisian population with colorectal carcinoma.

One of the most important pathways which are frequently affected in colorectal cancer is p53/ (MDM2)/p14ARF pathway. We aim to determine the methylation pattern of p14/ARF in relation to mutation of p53. This correlation was studied to investigate whether their alterations could be considered as a predictor factor of prognosis in colorectal cancer and whether it can be useful in early-stage diagnosis. Statistical analyses show that p14/ARF hypermethylation was correlated with rectum location (p = 0.004), primary TNM stage (p = 0.016), and advanced Astler-Coller stage (p = 0.024). The RT-PCR that revel 31 % of patients did not express p14/ARF mRNA or at very low level. A high concordance between CpG hypermethylation and the low levels (p < 0.005) was shown. In addition, our analyses demonstrate that patients with mutation in the p53 gene have a lack of the protein expression (p < 0.005). This category with negative expression of p53 had a shorter survival rate (p < 0.005). On the one hand, MSP pattern of p14/ARF were correlated with a lack of p53 expression (p = 0.007). We found that p53/p14ARF pathway was frequently deregulated among our patients. In our study, we demonstrate that hypermethylation of p14/ARF occurs early during CRC tumorogenesis. However, we did not find correlation between p14/ARF and survival. These results suggest that p14/ARF methylation pattern may constitute a predictor factor of CRC in early stage but it could not be considered as a prognostic factor. On the other hand and because of the reversibility of the methylation mechanism, it may be appropriate to target the demethylation of p14/ARF to develop new drogues for CRC.

Relationship between MDM2 and p53 alterations in colorectal cancer and their involvement and prognostic value in the Tunisian population.

BACKGROUND: The prevalence of p53 mutations in colorectal cancer could reach 90%. The most important regulator of this protein that was identified originally was the Murine Double Minute2 (MDM2) oncoprotein, by which the levels of p53 were fixed through an autoregulatory feedback loop. In cancer cases, the overexpression of MDM2 deregulates this feedback, and the signaling pathway between MDM2 and p53 is blocked. MATERIALS AND METHODS: We genotyped 167 patients and 167 healthy blood donors to determinate the mutational status of MDM2 and p53. Immunohistochemical analysis was performed on tumor and normal mucosa. RESULTS: The MDM2 polymorphism study showed a higher distribution of MDM2 SNP309 in tumors compared with healthy controls. At the same time, the majority of samples with SNP309 indicated a positive expression of MDM2 protein in the tumor. In this case, we found a first significant association between p53 expression and the single-strand conformational polymorphism analysis and a second association between the MDM2 polymorphism and p53 mutation. Moreover, the nuclear overexpression of MDM2 and SNP309 was significantly related to a higher mortality rate. CONCLUSIONS: In this work we wanted to highlight the role, which is becoming increasingly important, of MDM2. In fact, we conclude that the effects of MDM2 SNP309 may be considered a valuable prognostic marker to predict poor outcome for Tunisian patients with colorectal cancer.