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.

Rare single-nucleotide variants of MLH1 and MSH2 genes in patients with Lynch syndrome

BACKGROUND

Approximately 5% of colorectal cancers (CRCs) are hereditary. Lynch syndrome (LS), also known as hereditary nonpolyposis colorectal cancer (HNPCC), is the most common form of recognized hereditary CRC. Although Iran, as a developing country, has a high incidence of CRC, the spectrum of variants has yet to be thoroughly investigated.

AIMS

This study aimed to investigate pathogenic and non-pathogenic variants in MLH1 and MSH2 genes in Iranian patients with suspected Lynch syndrome (sLS).

METHODS AND RESULTS

In the present study, 25 peripheral blood samples were collected from patients with sLS and high microsatellite instability (MSI-H). After DNA extraction, all samples underwent polymerase chain reaction and Sanger sequencing to identify the variants in the exons of MLH1 and MSH2 genes. The identified variants were interpreted using prediction tools, and were finally reported under ACMG guidelines. In our study population, 13 variants were found in the MLH1 gene and 8 in the MSH2 gene. Interestingly, 7 of the 13 MLH1 variants and 3 of the 8 MSH2 variants were novel, whereas the remaining variants were previously reported or available in databases. In addition, some patients with sLS did not have variants in the exons of the MLH1 and MSH2 genes. The variants detected in the MLH1 and MSH2 genes had specific characteristics regarding the number, area of occurrence, and their relationship with demographic and clinicopathologic features.

CONCLUSION

Overall, our results suggest that analysis of MLH1 and MSH2 genes alone is insufficient in the Iranian population, and more comprehensive tests are recommended for detecting LS.

An update of the variant spectrum of the APC gene in Iranian familial adenomatous polyposis patients

Familial adenomatous polyposis (FAP) is an autosomal dominant colorectal cancer syndrome that is characterized by the development of multiple adenomas in the colon and rectum with high penetrance rates. This disease has specific features like the occurrence of pathogenic variations in the APC gene and diverse FAP phenotypes due to the occurrence region. In this study we aimed to evaluate pathogenic variants in exons of the APC gene in Iranian patients with FAP. A total of 35 FAP individuals were referred to the gastroenterology ward of Taleghani Hospital. As the aim of the study was to study the germline variations in the participants, the peripheral blood was collected and after the DNA extraction, PCR, and Sanger sequencing processes for the APC gene, the results were evaluated by the ACMG classification guidelines to report their pathogenicity. Accordingly, out of eight specific detected variants, three of them were novel, and the rest were reported previously. These eight variants were all truncating protein and pathogenic, and they were limited to 849-1378 codons. Overall, detected variants revealed discrepancies and parallels with previous reported cases in terms of quantity, occurrence region, and association with demographic and clinicopathological characteristics of patients. The spectrum of detected variants and the patient's phenotype showed distinct characteristics, such as occurrence in specific regions and the absence of extracolonic symptoms like Congenital hypertrophy of the retinal pigment epithelium (CHRPE). These findings open the path to comprehending the typical symptoms, their rarity, and their occurrence in the Iranian population and also due to the facts, we found that the studying of the APC gene alone for diagnosing FAP disease is not sufficient, and considering other genes are completely rational in the case of sequencing and studying the variants.

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.

Prognostic Value of BRAF and KRAS Mutation in Relation to Colorectal Cancer Survival in Iranian Patients: Correlated to Microsatellite Instability

PURPOSE

To evaluate the prognostic role of BRAF and KRAS mutations after adjustment for microsatellite instability (MSI) in Iranian colorectal cancer (CRC) patients.

METHODS

BRAF and KRAS mutations and MSI status were assessed in 258 Iranian subjects with CRC. Two hundred fifty-eight consecutive stages I-IV CRC patients, who underwent surgical resection of adenocarcinoma from 2012 to 2016, were enrolled in the research. Pyrosequencing and Cast-PCR methods were used to the detection of KRAS and BRAF mutations. Kaplan-Meier and Cox regression were employed to estimate hazard ratios (HR) for the association between BRAF and KRAS mutation and overall survival (OS).

RESULTS

KRAS and BRAF mutations were detected in 36 (14%) and 15 (5.8%) cases of 258 patients with CRC, respectively. BRAF mutations that all comprised V600E and KRAS mutations was found in codon 12 and 13 (80.6% and 19.4%), respectively. KRAS mutations were detected in 19 (15.4%) patients of 123 microsatellite stable (MSS) CRC and it is significantly associated with tumor location and metastasis. BRAF and KRAS mutant vs. wild type of BRAF and KRAS, 5-year OS was 73.3% vs. 82.3% and 83.3% vs. 81.5% (long-rank P > 0.05), respectively. KRAS mutant vs. KRAS-wild-type tumors in MSS/MSI-L status CRC patients, 5-year OS was 78.9% vs. 90.4% (long-rank p = 0.046).

CONCLUSION

The present study revealed that BRAF and KRAS mutations were not related to the worse overall survival, while KRAS mutation can be a prognostic factor for overall survival in sporadic microsatellite-stable (MSS) status in Iranian CRC patients.

HER2+ mCRC patients with exon 20 R784G substitution mutation do not respond to the cetuximab therapy

The human epidermal growth factor 2 (HER2) gene undergoes various mutations that could alter its activity or respond to the antibody therapies. Cetuximab, a known anti-EGFR monoclonal antibody (mAB), is widely administered in metastatic colorectal cancer (mCRC) cases. Here we identified mCRC patients who did not respond to cetuximab (500 mg/m² , q2w) after fluoropyrimidine/oxaliplatin regimen failure. Tumor samples were examined with immunohistochemistry for protein distribution, polymerase chain reaction (PCR) sequencing for mutation detection and real-time PCR for mRNA expression pattern analysis between cetuximab sensitive and resistance patients. The conformational differences of normal and mutated protein structures were predicted by bioinformatics analysis. The 5-year survival rates of target groups were estimated using the Kaplan-Meier method. Immunohistochemistry showed that all cases had high level of HER2 protein. No K-Ras or B-Raf mutation was observed among the study population; however, cetuximab resistance patients harbored a somatic mutation R784G at the exon 20 region of HER2 coding sequence. According to bioinformatics analysis, this mutation caused a notable misfold in protein conformation. Meanwhile, survival analysis showed R784G mutated mCRC patients had shortened survival rate compared with the mCRC cases with wild-type HER2. Collectively, these data report a new mechanism of resistance to cetuximab and might be applicable in modifying new therapeutic strategies for HER2 involved cancers.

Coexistence of KRAS and BRAF Mutations in Colorectal Cancer: A Case Report Supporting The Concept of Tumoral Heterogeneity

The detection of KRAS and BRAF mutations is a crucial step for the correct therapeutic approach and predicting the epidermal growth factor receptor (EGFR)-targeted therapy resistance of colorectal carcinomas. The concomitant KRAS and BRAF mutations occur rarely in the colorectal cancers (CRCs) with the prevalence of less than 0.001% of the cases. In patients with KRAS-mutant tumors, BRAF mutations should not regularly be tested unless the patient is participating in a clinical trial enriching for the presence of KRAS or BRAF-mutated tumor. The current report demonstrates a case with advanced adenocarcinoma of the colon showing the coexistence of KRAS and BRAF mutations and may have profound clinical implications for disease progression and therapeutic responses.

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).