Unmasking early colorectal cancer clues: in silico and in vitro investigation of downregulated IGF2, SOCS1, MLH1, and CACNA1G in SSA polyps.

BACKGROUND AND AIM: Colorectal cancer (CRC) originates from pre-existing polyps in the colon. The development of different subtypes of CRC is influenced by various genetic and epigenetic characteristics. CpG island methylator phenotype (CIMP) is found in about 15-20% of sporadic CRCs and is associated with hypermethylation of certain gene promoters. This study aims to find prognostic genes and compare their expression and methylation status as potential biomarkers in patients with serrated sessile adenomas/polyps (SSAP) and CRC, in order to evaluate which, one is a better predictor of disease. METHOD: This study employed a multi-phase approach to investigate genes associated with CRC and SSAP. Initially, two gene expression datasets were analyzed using R and Limma package to identify differentially expressed genes (DEGs). Venn diagram analysis further refined the selection, revealing four genes from the Weissenberg panel with significant changes. These genes, underwent thorough in silico evaluations. Once confirmed, they proceeded to wet lab experimentation, focusing on expression and methylation status. This comprehensive methodology ensured a robust examination of the genes involved in CRC and SSAP. RESULT: This study identified cancer-specific genes, with 8,351 and 1,769 genes specifically down-regulated in SSAP and CRC tissues, respectively. The down-regulated genes were associated with cell adhesion, negative regulation of cell proliferation, and drug response. Four highly downregulated genes in the Weissenberg panel, including CACNA1G, IGF2, MLH1, and SOCS1. In vitro analysis showed that they are hypermethylated in both SSAP and CRC samples while their expressions decreased only in CRC samples. CONCLUSION: This suggests that the decrease in gene expression could help determine whether a polyp will become cancerous. Using both methylation status and gene expression status of genes in the Weissenberg panel in prognostic tests may lead to better prognoses for patients.

Evaluating CD4 and Foxp3 mRNA Expression in Tissue Specimens of Celiac Disease and Colorectal Cancer Patients.

OBJECTIVE: Celiac disease (CD) and colorectal cancer (CRC) are distinct gastrointestinal conditions with a debated association. This study aimed to evaluate the mRNA expression of CD4 and Foxp3 in tissue specimens of CD and CRC patients. The findings can provide valuable insights into the complex connection between these different gastrointestinal conditions. METHODS: Tissue samples from 100 CRC patients, 50 CD patients, and 50 healthy controls (HCs) were collected. RNA extraction, cDNA synthesis, and quantitative real-time PCR were performed. Statistical analysis was conducted using ANOVA and Pearson's correlation test. RESULT: CD4 mRNA expression was significantly higher in CRC patients compared to CD patients and HCs (P<0.0001 for both). Foxp3 mRNA expression was significantly higher in CD patients compared to CRC patients and HCs (P<0.0001 for both). Clinicopathological characteristics did not correlate significantly with gene expression levels. CONCLUSION: This study reveals differential expression patterns of CD4 and Foxp3 mRNA in CRC and CD patients. Upregulated CD4 mRNA suggests its potential role in promoting tumor growth, while increased Foxp3 mRNA expression may reflect an immunosuppressive mechanism in CD pathogenesis. These findings provide insights into the molecular and immunological aspects of CRC and CD, warranting further studies for potential therapeutic strategies.

A novel stop codon mutation in STK11 gene is associated with Peutz-Jeghers Syndrome and elevated cancer risk: a case study.

Based on the analysis of patients with Peutz-Jeghers syndrome (PJS), Serine threonine kinase11 (STK11) is known as a tumor suppressor gene, which is involved in cell polarization, regulation of apoptosis, and DNA damage response. In this case report study, we examined STK11 gene sequencing in a 42-year-old woman with mucocuta neous pigmentation and positive family history. Endoscopy and colonoscopy showed >1000 polyps throughout the stomach/colon (PJ-type hamartomas). The larger polyp in the stomach was resected and the small bowel imaging detected multiple jejunum/ileum small polyps. The data released from the sequencing results revealed five alterations in exons 1 to 5. The major mutation in stop codon was reported as converted to the amino acid tryptophan (TRP) to tyrosine (TER). The TGG codon was converted to TAG by mutation. Finally, another novel mutation in STK11 stop codon as a 'de novo' variant was seen. It is predicted that stop codon mutations make the affected person susceptible to developing colorectal cancer.

Low Level of Microsatellite Instability Correlates with Poor Clinical Prognosis in Stage II Colorectal Cancer Patients.

The influence of microsatellite instability (MSI) on the prognosis of colorectal cancer (CRC) requires more investigation. We assessed the role of MSI status in survival of individuals diagnosed with primary colorectal cancer. In this retrospective cross-sectional study the MSI status was determined in 158 formalin-fixed paraffin-embedded tumors and their matched normal tissues from patients who underwent curative surgery. Cox proportional hazard modeling was performed to assess the clinical prognostic significance. In this study we found that MSI-H tumors were predominantly located in the colon versus rectum (p = 0.03), associated with poorer differentiation (p = 0.003) and TNM stage II/III of tumors (p = 0.02). In CRC patients with stage II, MSI-L cases showed significantly poorer survival compared with patients who had MSI-H or MSS tumors (p = 0.04). This study indicates that MSI-L tumors correlate with poorer clinical outcome in patients with stage II tumors (p = 0.04) or in tumors located in the colon (p = 0.02). MSI-L characterizes a distinct subgroup of CRC patients who have a poorer outcome. This study suggests that MSI status in CRC, as a clinical prognostic marker, is dependent on other factors, such as tumor stage and location.

Lack of BRAFV600E mutation in stage I and II of colorectal cancer.

AIM: We aimed to explore the frequency of BRAFV600E mutation in Iranian patients with colorectal cancer (CRC) as well as its association with clinic pathological characteristic of patients. BACKGROUND: CRC is the third leading cause of cancer related death. There is a growing body of data showing the association of BRAFV600E mutation with malignant transformation and clinical outcome of different tumors, including CRC. These findings suggest that BRAFV600E mutation can be used as diagnostic and/or prognostic biomarker for management of cancer patients. PATIENTS AND METHODS: A total of 85 patients with sporadic tumor were recruited. BRAFV600E mutation was investigated using sequencing of extracted DNAs from formalin-fixed paraffin-embedded (FFPE) tumor tissues. Electropherograms were analyzed using Laser-gene 6 software. RESULTS: More than 95% of patients were in stage I and II and none of them were in stage IV. Patients were mostly below 55 years old and tumors were dominantly located in the distal colon. Of note, no BRAFV600E mutations were detected in our population. CONCLUSION: Our results showed no V600E mutation in the BRAF gene in stage I and II of CRC patients. Further studies in multi-center settings are warranted to examine the prognostic and/or predictive value of this marker in different stages of colorectal cancer patients.

Polymorphism of SMAD7 gene (rs2337104) and risk of colorectal cancer in an Iranian population: a case-control study.

AIM: The purpose of this study was to evaluate the influence of intronic polymorphism of the SMAD7 (Mothers Against Decantaplegic Homolog 7) gene (rs2337104) on the risk of colorectal cancer (CRC) and clinicopathological features in an Iranian population. BACKGROUND: SMAD7 has been identified as an antagonist of transforming growth factor beta (TGF-b)-mediating fibrosis, carcinogenesis, and inflammation. Regarding to the recent genome-wide scan, a risk locus for colorectal cancer at 18q21 has been found, which maps to the SMAD7 gene. PATIENTS AND METHODS: This case-control study was performed on 109 CRC patients and 109 healthy controls recruited in Taleghani Hospital. The genotyping of all samples were done by TaqMan assay via an ABI 7500 Real Time PCR System (Applied Biosystems) with DNA from peripheral blood. The association of this polymorphism with the risk of CRC and clinicopathological features was investigated. RESULTS: Our results indicated that there were no significant association between genotypic and allelic frequencies of SMAD7 polymorphism (rs2337104) and CRC risk in our population. Although the T allele is the most frequent one in this population and its frequency was 86.7% in patients compared with 91.7% in controls (OR=1.705, 95% CI= 0.916-3.172). Also, the SMAD7 genotypes were not associated with any clinicopathological characteristics in CRC patients (P>0.05). CONCLUSION: For the first time, this study results revealed that this SMAD7 polymorphism couldn't be a potential risk factor for CRC or a prognostic biomarker for prediction of clinicopathological features in an Iranian population. A large-scale case-control study is needed to validate our results.

The role of kras mutations and MSI status in diagnosis of colorectal cancer.

AIM: The aim of the current investigation was to examine the profile of Kras mutations accompanied with MSI (microsattelite instability) status in polyps and colorectal carcinoma tissues in an Iranian population. BACKGROUND: Kras mutations in colorectal cancer cause resistance to anti-Epidermal Growth Factor Receptor (EGFR). So it can be considered as a true indicator of EGFR pathway activation status. Kras mutations can be detected in approximately 30% to 40% of all patients with colorectal cancer. The most hot spot of the gene is located in exons 2 and 3. PATIENTS AND METHODS: In this study we examined exons 2 and 3 Kras gene using polymerase chain reactions and subsequent sequencing of the exons in 95 patients with sporadic colorectal cancer including 48 tumors and 47 polyps. This study was performed using biopsy samples from the patients. We sequenced the Kras gene in a panel of human colorectal tumors and polyps in addition to detecting MSI status using fluorescent technique. RESULTS: We could detect 6 mutations in tumors including 5 mutations in codon 12 and one mutation in codon 13. Moreover, in polyps 2 mutations were determined in codon 13 and one in codon 12. Microsatellite instability assay revealed the presence of 5 and 6 MSI in tumors and polyps, respectively. Among the MSI mononucleotide markers, NR-21 marker demonstrated the most frequency (60%) in the both groups. CONCLUSION: Our findings showed that probably the profile of mutations in tumors is not entirely compatible with the pattern of mutations in polyps. However, just one of the mutations, Gly12Asp, was similar in both groups.

Impact of EXO1 polymorphism in susceptibility to colorectal cancer.

BACKGROUND AND AIM: One candidate gene for colorectal cancer (CRC) susceptibility is exonuclease 1 (EXO1). It is a member of RAD2 nuclease family, which plays a major role in mismatch repair, DNA replication, and recombination. Single-nucleotide polymorphisms are shown to be related with cancer incidence. The aim of the present study was to examine the association between the L757P polymorphism at exon 13 of the EXO1 gene and the risk of CRC in Iranian patients. METHODS: In this case-control study, 90 cases and 98 healthy control samples were analyzed genetically. The EXO1 polymorphism, P757L, was analyzed by polymerase chain reaction-restriction fragment length polymorphism. The obtained polymorphisms were examined for the relationship with CRC risk and also clinicopathological characteristics. RESULTS: Our findings showed that patients with the Leu/Leu genotype have a reduced risk of CRC (adjusted odds ratio [OR] = 0.192, 95% confidence interval [CI]: 0.040-0.921) when the Pro/Leu and Pro/Pro genotypes were blended and they were considered as the reference. The Leu/Leu genotype also showed a reduced risk (adjusted OR = 0.168, 95% CI: 0.034-0.816) when the Pro/Pro genotype was a reference; nevertheless, the Pro/Leu genotype did not reveal a significant association with CRC at the same status (adjusted OR = 0.686, 95% CI: 0.367-1.284). CONCLUSIONS: Our results provide evidence diagnosing that the Leu/Leu genotype of EXO1 showed an inverse association with CRC. In addition, despite other investigations, we could define a significant association between the Leu allele and CRC (p = 0.001).