Lack of association between miR-27a, miR-146a, miR-196a-2, miR-492 and miR-608 gene polymorphisms and colorectal cancer

Polymorphic Single-Nucleotide Variants in miRNA Genes and the Susceptibility to Colorectal Cancer: Combined Evaluation by Pairwise and Network Meta-Analysis, Thakkinstian's Algorithm and FPRP Criterium

BACKGROUND

Considerable epidemiological studies have examined the correlation between polymorphic single-nucleotide variants (SNPs) in miRNA genes and colorectal carcinoma (CRC) risk, yielding inconsistent results. Herein, we sought to systematically investigate the association between miRNA-SNPs and CRC susceptibility by combined evaluation using pairwise and network meta-analysis, the FPRP analysis (false positive report probability), and the Thakkinstian's algorithm.

METHODS

The MEDLINE, EMBASE, WOS, and Cochrane Library databases were searched through May 2024 to find relevant association literatures. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were computed by the pairwise meta-analysis. Network meta-analysis and the Thakkinstian's method were applied for determining the potentially optimal genetic models; additionally, the FPRP was used to identify noteworthy associations.

RESULTS

Totally, 39 case-control trials involving 18,028 CRC cases, and 21,816 normal participants were included in the study. Eleven SNPs within nine genes were examined for their predisposition to CRC. miR-27a (rs895819) was found to significantly increase CRC risk among overall population (OR 1.58, 95% CI: 1.32-1.89) and Asians (OR 1.62, 95% CI: 1.31-2.01), with the recessive models identified as the optimal models. Furthermore, miR-196a2 (rs11614913), miR-143/145 (rs41291957), and miR-34b/c (rs4938723) were significantly related to reduced CRC risk among Asian descendants under the optimal dominant (OR 0.75, 95% CI: 0.65-0.86), recessive (OR 0.72, 95% CI: 0.60-0.85), and recessive models (OR 0.69, 95% CI: 0.56-0.85), respectively. The results were also proposed by the network meta-analysis or the Thakkinstian's method and confirmed by the FPRP criterion.

CONCLUSION

The miR-27a (rs895819) is correlated with elevated CRC risk among overall population and Asians, and the recessive model is found to be optimal for predicting CRC risk. Additionally, the miR-196a2 (rs11614913), miR-143/145 (rs41291957), and miR-34b/c (rs4938723), with the dominant, recessive, and recessive models identified as the optimal, might confer protective effects against CRC among Asians.

mirSNPs as Potential Colorectal Cancer Biomarkers: A Systematic Review

Colorectal cancer (CRC) is the third most common neoplasm in the world and the second with the highest mortality rate. Single nucleotide polymorphisms (SNPs) in microRNA (miRNA) genes known as mirSNPs may be related to dysregulated miRNA expression in several neoplasms. This systematic review aims to investigate studies that investigate SNPs located in regions of miRNA genes that influence their expression and are associated with CRC, as well as their potential as biomarkers for the disease, based on the available literature. For this, searches were performed in public databases, including MEDLINE/PubMed, Embase, Web of Science, and Scopus. The rigorous review of the PRISMA 2020 guidelines and the methodological quality of these studies was assessed using the Newcastle-Ottawa scale and the Mixed Methods Assessment Tool. Of the 175 studies identified, 26 were considered eligible: 18 of them highlighted mirSNPs as potential biomarkers of risk and prognosis for CRC; 4 studies suggested a protective role; 1 study linked mirSNPs to treatment; 3 studies found no relevant evidence. These results highlight the importance of conducting further research on the topic, given the potential of these biomarkers to contribute to risk assessment, prognosis, and the development of therapeutic strategies for patients with CRC.

Genetic Variation in miR-27a Is Associated with Fluoropyrimidine-Associated Toxicity in Patients with Dihydropyrimidine Dehydrogenase Variants after Genotype-Guided Dose Reduction

Dihydropyrimidine dehydrogenase (DPYD) is the rate-limiting enzyme involved in the metabolism of fluoropyrimidine-based chemotherapy. However, single-nucleotide variants (SNVs) in DPYD only partially explain fluoropyrimidine-induced toxicity. The expression of DPYD has previously been shown to be regulated by microRNA-27a (miR-27a) and a common miR-27a SNV (rs895819) has been associated with an increased risk of toxicity in patients harboring a DPYD variant who received standard fluoropyrimidine dosing. We investigated if the miR-27a rs895819 SNV was associated with toxicity in DPYD wildtype patients and carriers of DPYD variants who received a reduced dose. The regulation of DPYD using miR-27a was investigated in HepG2 cells utilizing a miR-27a mimic. miR-27a overexpression decreased DPYD mRNA expression compared to control cells (p < 0.0001). In a cohort of patients that received pre-emptive DPYD genotyping, 45 patients had a DPYD variant and 180 were wildtype. Patients heterozygous for rs895819 had an increased risk of toxicity, which was seen in both patients who were wildtype for DPYD variants (OR (95%CI) = 1.99 (1.00-3.99)) and DPYD variant carriers (OR (95%CI) = 8.10 (1.16-86.21)). Therefore, miR-27a rs895819 may be a clinically relevant predictor of fluoropyrimidine-associated toxicities. Furthermore, toxicity was more profound in DPYD variant carriers, even after DPYD genotype-guided dose reduction. This suggests that patients may benefit from miR-27a genotyping to guide fluoropyrimidine dosing.

Association of miR-149 T>C and miR-196a2 C>T Polymorphisms with Colorectal Cancer Susceptibility: A Case-Control Study

The principal aim of the current study was to investigate the relationship between miR-149 T>C (rs2292832) and miR-196a2 C>T (rs11614913) small non-coding RNA polymorphisms and the risk of developing CRC in the Azerbaijani population. The study included 120 patients diagnosed with CRC and 125 healthy individuals. Peripheral blood samples were collected from all the subjects in EDTA tubes and DNA extraction was performed by salting out. Polymorphisms were determined using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. While comparing without gender distinction no statistical correlation was found between the heterozygous TC (OR = 0.66; 95% CI = 0.37-1.15; p = 0.142), mutant CC (OR = 1.23; 95% CI = 0.62-2.45; p = 0.550), and mutant C (OR = 1.03; 95% CI = 0.72-1.49; p = 0.859) alleles of the miR-149 gene and the CT (OR = 1.23; 95% CI = 0.69-2.20; p = 0.485), mutant TT (OR = 1.29; 95% CI = 0.67-2.47; p = 0.452), and mutant T (OR = 1.17; 95% CI = 0.82-1.67; p = 0.388) alleles of the miR-196a2 gene and the risk of CRC. However, among women, miR-149 TC (OR = 0.43; 95% CI = 0.19-1.01; p = 0.048) correlated with a reduced risk of CRC, whereas miR-196a2 CT (OR = 2.77; 95% CI = 1.13-6.79; p = 0.025) correlated with an increased risk of CRC. Our findings indicated that miR-149 T>C (rs2292832) might play a protective role in the development of CRC in female patients, whereas the miR-196a2 (rs11614913) polymorphism is associated with an increased risk of CRC in women in the Azerbaijani population, highlighting the importance of gender dimorphism in cancer etiology.

Impact of Mir196a-2 Genotypes on Colorectal Cancer Risk in Taiwan

We aimed to investigate the association between genotypes for mir146a and mir196a-2 and the risk of developing colorectal cancer (CRC). We used polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to determine the mir146a rs2910164 and mir196a-2 rs11614913 genotypes in 362 CRC patients and 362 controls. We also assessed the interactions between these genotypes and age, gender, smoking, alcohol consumption, and BMI status on CRC risk. Additionally, the serum expression level of mir196a-2 was quantified using quantitative reverse transcription-PCR. Our findings demonstrated that among the controls, the proportions of TT, CT, and CC genotypes of mir196a-2 rs11614913 were 32.3%, 48.1%, and 19.6%, respectively. As for the cases, the proportions were 24.6%, 45.0%, and 30.4%, respectively. Logistic regression analysis revealed that the CC genotype carriers had a 2.04-fold increased risk (95% confidence interval [CI] = 1.36-3.06, p = 0.0008). Furthermore, carriers of the CT + CC genotypes also exhibited a significant association with CRC risk (odds ratio [OR] = 1.46, 95% CI = 1.06-2.03, p = 0.0261). Moreover, carriers of the CC genotype had significantly higher serum levels of mir196a-2 compared to those with the TT genotype (p < 0.0001), indicating a genotype-phenotype correlation. No association was found regarding mir146a rs2910164. In conclusion, mir196a-2 rs2910164 genotypes, along with their associated expression, can serve as predictive markers for CRC risk.

A Review of IsomiRs in Colorectal Cancer

As advancements in sequencing technology rapidly continue to develop, a new classification of microRNAs has occurred with the discovery of isomiRs, which are relatively common microRNAs with sequence variations compared to their established template microRNAs. This review article seeks to compile all known information about isomiRs in colorectal cancer (CRC), which has not, to our knowledge, been gathered previously to any great extent. A brief overview is given of the history of microRNAs, their implications in colon cancer, the canonical pathway of biogenesis and isomiR classification. This is followed by a comprehensive review of the literature that is available on microRNA isoforms in CRC. The information on isomiRs presented herein shows that isomiRs hold great promise for translation into new diagnostics and therapeutics in clinical medicine.

Association between miR-146a rs2910164, miR-196a2 rs11614913, and miR-499 rs3746444 polymorphisms and the risk of esophageal carcinoma: A case-control study

MicroRNAs (miRNAs) are a group of small, non‐coding, and endogenous RNAs that regulate gene expression and over 50% of them are located at cancer‐related genomic regions or fragile sites. According to previous studies there is significant association of miRNA single nucleotide polymorphisms (SNPs) with tumorigenesis (e.g., esophageal cancer, hepatocellular cancer, gastric cancer, bladder cancer, breast cancer, lung cancer, and colon cancer), however, the conclusions have been inconsistent. To investigate the relationship between miR‐146a rs2910164 C > G, miR‐196a2 rs11614913 T > C, and miR‐499 rs3746444 A > G polymorphisms and the susceptibility to esophageal squamous cell cancer (ESCC) in the Chinese Han nationality, we recruited 829 cases and 1522 controls in our study. In this case–control study, our results suggest that the rs3746444 GG genotype increased ESCC risk [homozygote model: adjusted odds ratio (OR), 2.26; 95% CI, 1.33–3.83; p = 0.003, recessive model: adjusted OR, 2.34; 95% CI, 1.38–3.96; p = 0.002], which remained consistent after Bonferroni correction. There was no association of rs11614913 and rs2910164 polymorphisms with ESCC. After adjusting by age, sex, smoking, and drinking status and body mass index (BMI), the multiple logistic analysis suggested that rs11614913 T → C variation reduced ESCC susceptibility in females and in the ≥63 years old subgroups, while rs2910164 C → G variation increased ESCC risk in both two BMI subgroups.

Association of Polymorphisms in miR146a, an Inflammation-Associated MicroRNA, with the Risk of Idiopathic Recurrent Spontaneous Miscarriage: A Case-Control Study

It has been established that microRNAs (miRNAs) are involved in the regulation of immune responses and serve as biomarkers of inflammatory diseases as well as recurrent spontaneous miscarriage (RSM). Herein, we aimed to study the relationship between three functional miR146a gene polymorphisms with idiopathic RSM (IRSM) susceptibility. We recruited 161 patients with IRSM and 177 healthy women with at least one live birth and without a history of abortion. Genotyping was performed using RFLP-PCR and ARMS-PCR methods. We found that the rs6864584 T/C decreased the risk of IRSM under dominant TT+TC vs. CC (OR = 0.029) and allelic C vs. T (OR = 0.028) contrast models. Regarding rs2961920 A/C and rs57095329 A/G polymorphisms, the enhanced risk of IRSM was observed under different genetic contrasted models, including the codominant CC vs. AA (OR = 2.81 for rs2961920) and codominant GG vs. AA (OR = 2.36 for rs57095329). After applying a Bonferroni correction, haplotype analysis revealed a 51% decreased risk of IRSM regarding the ACA genotype combination. This is the first study reporting that miR146a rs57095329 A/G, rs2961920A/C, and rs6864584 T/C polymorphisms are associated with the risk of IRSM in a southern Iranian population. Performing replicated case-control studies on other ethnicities is warranted to outline the precise effects of the studied variants on the risk of gestational trophoblastic disorders.

Biological Functions and Molecular Mechanisms of MiR-608 in Cancer

In recent years, microRNAs (miRNAs) have attracted much attention because of their prominent role in cancer. An increasing number of studies have shown that miRNAs play an important role in a variety of tumors. miR-608 has been reported to be decreased in cancers, especially in solid tumors. miR-608 is regarded as a tumor suppressor, which has been verified through a large number of experiments both in vivo and in vitro. miR-608 participates in many biological processes, including cell proliferation, invasion, migration, and apoptosis, by inhibiting transmembrane proteins and many signaling pathways. Here, we summarize the expression profile and biological functions and mechanism of miR-608, suggesting that miR-608 is an ideal diagnostic and prognostic biomarker and a treatment target for cancer.

Single Nucleotide Polymorphisms in microRNA Genes and Colorectal Cancer Risk and Prognosis

There is growing interest in single nucleotide polymorphisms (SNPs) in the genes of microRNAs (miRNAs), which could be associated with susceptibility to colorectal cancer (CRC) and therefore for prognosis of the disease and/or treatment response. Moreover, these miRNAs-SNPs could serve as new, low-invasive biomarkers for early detection of CRC. In the present article, we performed a thorough review of different SNPs, which were investigated for a correlation with the CRC risk, prognosis, and treatment response. We also analyzed the results from different meta-analyses and the possible reasons for reported contradictory findings, especially when different research groups investigated the same SNP in a gene for a particular miRNA. This illustrates the need for more case-control studies involving participants with different ethnic backgrounds. According to our review, three miRNAs-SNPs-miR-146a rs2910164, miR-27a rs895819 and miR-608 rs4919510-appear as promising prognostic, diagnostic and predictive biomarkers for CRC, respectively.

Effect of miR-196a2 rs11614913 Polymorphism on Cancer Susceptibility: Evidence From an Updated Meta-Analysis

Background:MiR-196a2 rs11614913 polymorphism has been studied in a wide range of cancers throughout the years. Despite a large number of epidemiological studies performed in almost all ethnic populations, the contribution of this polymorphism to cancer risk is still inconclusive. Therefore, this updated meta-analysis was performed to estimate a meticulous correlation between miR-196a2 rs11614913 variant and cancer susceptibility. Methods: A systematic study search was carried out using PubMed, ScienceDirect, CNKI, EMBASE, Scopus, and Google Scholar databases following PRISMA guidelines to find necessary literature up to December 15, 2021. Pooled odds ratios with corresponding 95% confidence intervals were estimated using RevMan 5.4 based on ethnicities, cancer types, control sources, and genotyping methods. Results: A total of 152 studies, including 120 135 subjects (53 818 patients and 66 317 controls; 140 studies, after removing studies that deviated from HWE: 51 459 cases and 62 588 controls), were included in this meta-analysis. Quantitative synthesis suggests that the miR-196a2 rs11614913 genetic variant is significantly correlated with the reduced risk of overall cancer in CDM2, CDM3, RM, and AM (odds ratio < 1 and P < .05). It is also observed from ethnicity-based subgroup analysis that rs11614913 polymorphism is significantly (P < .05) linked with cancer in the Asian (in CDM2, CDM3, RM, AM) and the African population (in CDM1, CDM3, ODM). Stratified analysis based on the cancer types demonstrated a significantly decreased correlation for breast, hepatocellular, lung, and gynecological cancer and an increased association for oral and renal cell cancer. Again, the control population-based subgroup analysis reported a strongly reduced correlation for HB population in CDM2, RM, and AM. A substantially decreased risk was also observed for other genotyping methods in multiple genetic models. Conclusions:MiR-196a2 rs11614913 variant is significantly correlated with overall cancer susceptibility. Besides, rs11614913 is correlated with cancer in Asians and Africans. It is also correlated with breast, gynecological, hepatocellular, lung, oral, and renal cell cancer.

MicroRNAs as important contributors in the pathogenesis of colorectal cancer

Colorectal cancer (CRC) is the third most fatal and fourth most frequently diagnosed neoplasm in the world. Numerous non-coding RNAs have been shown to contribute in the development of CRC. MicroRNAs (miRNAs) are among the mostly assessed non-coding RNAs in CRC. These transcripts influence expression and activity of TGF-β, Wnt/β-catenin, MAPK, PI3K/AKT and other CRC-related pathways. In the context of CRC, miRNAs interact with long non-coding RNAs to influence CRC course. Stool and serum levels of miRNAs have been used to distinguish CRC patients from healthy controls, indicating diagnostic roles of these transcripts in CRC. Therapeutic application of miRNAs in CRC has been assessed in animal models, yet has not been verified in clinical settings. In the current review, we have provided a recent update on the role of miRNAs in CRC development as well as diagnostic and prognostic approaches.

Novel Biomarkers in the Diagnosis of Benign and Malignant Gastrointestinal Diseases

BACKGROUND

Various noninvasive biomarkers have been used in the diagnosis, prognosis, and treatment of different gastrointestinal (GI) diseases for years. Novel technological developments and profound perception of molecular processes related to GI diseases over the last decade have allowed researchers to evaluate genetic, epigenetic, and many other potential molecular biomarkers in different diseases and clinical settings. Here, we present a review of recent and most relevant articles in order to summarize major findings on novel biomarkers in the diagnosis of benign and malignant GI diseases.

SUMMARY

Genetic variations, noncoding RNAs (ncRNAs), cell-free DNA (cfDNA), and microbiome-based biomarkers have been extensively analyzed as potential biomarkers in benign and malignant GI diseases. Multiple single-nucleotide polymorphisms have been linked with a number of GI diseases, and these observations are further being used to build up disease-specific genetic risk scores. Micro-RNAs and long ncRNAs have a large potential as noninvasive biomarkers in the management of inflammatory bowel diseases and GI tumors. Altered microbiome profiles were observed in multiple GI diseases, but most of the findings still lack translational clinical application. As of today, cfDNA appears to be the most potent biomarker for early detection and screening of GI cancers. Key Messages: Novel noninvasive molecular biomarkers show huge potential as useful tools in the diagnostics and management of different GI diseases. However, the use of these biomarkers in real-life clinical practice still remains limited, and further large studies are needed to elucidate the ultimate role of these potential noninvasive clinical tools.

Lack of association between miR-146a rs2910164 C/G locus and colorectal cancer: from a case-control study to a meta-analysis

Previous studies suggested that miR-146a rs2910164 (C/G) locus was predicted to influence the risk of cancer. However, the relationship of miR-146a rs2910164 locus with colorectal cancer (CRC) susceptibility was controversial. We recruited 1003 CRC patients and 1303 controls, and performed a case–control study to clarify the correlation of miR-146a rs2910164 locus with CRC risk. Subsequently, a comprehensive meta-analysis was conducted to verify our findings. In the case–control study, we suggested that miR-146a rs2910164 variants did not alter CRC risk (CG vs. CC: adjusted P=0.465; GG vs. CC: adjusted P=0.436, CG/GG vs. CC: adjusted P=0.387 and GG vs. CC/CG: adjusted P=0.589), even in subgroup analysis. Next, we conducted a pooled-analysis to identify the correlation of miR-146a rs2910164 locus with CRC risk. In this pooled-analysis, 7947 CRC cases and 12,168 controls were included. We found that miR-146a rs2910164 polymorphism did not influence the risk of CRC (G vs. C: P=0.537; GG vs. CC: P=0.517, CG/GG vs. CC: P=0.520 and GG vs. CC/CG: P=0.167). Our findings suggest that miR-146a rs2910164 C/G polymorphism is not correlated with the susceptibility of CRC. In the future, more case–control studies are needed to confirm our results.

Association between miR-492 rs2289030 G>C and susceptibility to Hirschsprung disease in southern Chinese children

OBJECTIVE

Hirschsprung disease (HSCR) originates from disruption of normal neural crest cell migration, differentiation, and proliferation during the fifth to eighth weeks of gestation. This results in the absence of intestinal ganglion cells in the distal intestinal tract. However, genetic variations affecting embryonic development of intestinal ganglion cells are unclear. Therefore, this study aimed to investigated the potential value of miR-492 rs2289030 G>C as a marker of susceptibility to HSCR.

METHODS

In this case-control study in southern Chinese children, we collected samples from 1473 controls and 1470 patients with HSCR. TaqMan genotyping of miR-492 rs2289030 G>C was performed by real-time fluorescent quantitative polymerase chain reaction.

RESULTS

Multivariate logistic regression analysis showed that there was no significant association between the presence of the miR-492 rs2289030 G>C polymorphism and susceptibility to HSCR by evaluating the values of pooled odds ratios and 95% confidence intervals. Similarly, among different HSCR subtypes, rs2289030 G>C was also not associated with HSCR in hierarchical analysis.

CONCLUSIONS

Our results suggest that the miR-492 rs2289030 G>C polymorphism is not associated with susceptibility to HSCR in southern Chinese children. These results need to be further confirmed by investigating a more diverse ethnic population of patients with HSCR.

MiRNA-146a rs2910164 Confers a Susceptibility to Digestive System Cancer: A Meta-Analysis Involving 59,098 Subjects

BACKGROUND

MicroRNA (miR)-146a might participate in the occurrence of malignant tumor. The aim of the current investigation was to evaluate the relationship of microRNA-146a (miR-146a) rs2910164 C > G locus to the development of digestive system cancer (DSC).

METHODS

We retrieved publications from PubMed, China Biology Medicine and EMBASE databases up to August 29, 2019. Finally, 56 independent case-control studies with 59,098 participants were included. The strength of the relationship between rs2910164 locus and a risk of DSC was assessed. The power value was also calculated in this study.

RESULTS

We identified a correlation of rs2910164 locus in miR-146a with DSC development in dominant model (P = .035; power value = 0.994). MiR-146a rs2910164 locus was also identified to be correlated with a risk of DSC in Asians (GG/CG vs. CC: P = .033; power value = 0.989). Sensitivity analysis revealed that any individual study could not alter the final decision. In our study, no significant bias was found among these included studies (P > .1). The results of heterogeneity analysis suggested that small sample size (<1000 subjects), colorectal carcinoma, Asians, gastric carcinoma, esophageal squamous cell carcinoma, hepatocellular cancer, hospital-based study and high-quality score (≥7.0) subgroups contributed the heterogeneity to our findings. Galbraith radial plot determined that eleven outliers contributed to the main heterogeneity.

CONCLUSION

In summary, this meta-analysis highlights that rs2910164 locus might be implicated in the risk of DSC. More studies are, therefore, needed to confirm our results.

Investigating the role of microRNA-27a gene polymorphisms and its interactive effect with risk factors in gastrointestinal cancers

Gastrointestinal (GI) cancers are known to have a high incidence worldwide and require an early diagnosis to successfully treat them, providing higher survival rates and better quality of life for the patients. MicroRNA-27a is a well-known oncogene that plays a significant role in various GI cancers. It is known to upregulate the expression of numerous oncogenes leading to cancer progression. The miR-27a harbors two polymorphisms rs895819 and rs11671784 which alter the disease susceptibility by interfering with the maturation and expression of miR-27a. In the current study, we aimed to investigate the role played by these polymorphisms in cancers of the GI tract. We conducted a case-control study with 210 GI cancer cases and 210 cancer-free controls to analyze the effect of these polymorphisms. The rs895819 polymorphism was genotyped using PCR-RFLP, and rs11671784 was genotyped on a MassARRAY platform. The association analysis failed to bring out any significant association of the polymorphisms with GI cancer risk. However, genotype-phenotype interaction analysis revealed that the rs895819 was found to increase the risk GI cancers along with the presence of risk factors such as socioeconomic status, diabetes mellitus, hypertension, alcohol consumption, and tobacco chewing.

Common variation in FAM155A is associated with diverticulitis but not diverticulosis

Colonic diverticulosis is a very common condition. Many patients develop diverticulitis or other complications of diverticular disease. Recent genome-wide association studies (GWAS) consistently identified three major genetic susceptibility factors for both conditions, but did not discriminate diverticulititis and diverticulosis in particular due the limitations of registry-based approaches. Here, we aimed to confirm the role of the identified variants for diverticulosis and diverticulitis, respectively, within a well-phenotyped cohort of patients who underwent colonoscopy. Risk variants rs4662344 in Rho GTPase-activating protein 15 (ARHGAP15), rs7609897 in collagen-like tail subunit of asymmetric acetylcholinesterase (COLQ) and rs67153654 in family with sequence similarity 155 A (FAM155A) were genotyped in 1,332 patients. Diverticulosis was assessed by colonoscopy, and diverticulitis by imaging, clinical symptoms and inflammatory markers. Risk of diverticulosis and diverticulitis was analyzed in regression models adjusted for cofactors. Overall, the variant in FAM155A was associated with diverticulitis, but not diverticulosis, when controlling for age, BMI, alcohol consumption, and smoking status (ORadjusted 0.49 [95% CI 0.27-0.89], p = 0.002). Our results contribute to the assessment specific genetic variants identified in GWAS in the predisposition to the development of diverticulitis in patients with diverticulosis.

Association of microRNA-27a rs895819 polymorphism with the risk of cancer: An updated meta-analysis

BACKGROUND

MiR-27a rs895819 polymorphism is considered as a tumor- related susceptibility gene. Previous meta-analyses evaluated the association the association between miR-27a rs895819 and cancer risk, but the results were inconsistent. The present meta-analysis was carried out to better estimate the correlation of rs895819 and cancer susceptibility.

METHODS

We searched several databases to identify relevant studies, including PubMed, EMBASE and the Cochrane Controlled Trials Register. The odds ratios (ORs) with 95% confidence intervals (CIs) were used to estimate the association between miR-27a rs895819 and cancer risk.

RESULTS

The overall analysis showed the miR-27a rs895819 was not associated with cancer susceptibility in all models (dominant model: OR = 1.02, 95% CI:0.94-1.10, p = 0.632; recessive model: OR = 1.05, 95% CI: 0.92-1.76, p = 0.474; homozygote model: OR = 1.06, 95% CI: 0.91-1.23, p = 0.439; heterozygote model: OR = 1.00, 95% CI: 0.93-1.08, p = 0.934; and allele model: OR = 1.02, 95% CI: 0.96-1.09, p = 0.486). Interestingly, rs895819 A > G was significantly associated with colorectal cancer risk in recessive model (OR = 1.54, 95% CI: 1.29-1.83, p < 0.001), homozygote model (OR = 1.59, 95% CI: 1.31-1.92, p < 0.001), and allele model (OR = 1.22, 95% CI: 1.10-1.34, p < 0.001). In addition, rs895819 polymorphism was correlated with increased risk of breast cancer in the recessive model (OR = 0.81, 95% CI: 0.66-1.00, p = 0.046) and allele model (OR = 0.89, 95% CI: 0.80-0.98, p = 0.021).

CONCLUSIONS

Our results suggested that rs895819 polymorphism was correlated with increased risk of colorectal cancer and breast cancer, but not all types of cancer.

A New Method for Biostatistical miRNA Pattern Recognition with Topological Properties of Visibility Graphs in 3D Space

Visibility is a very important topic in computer graphics and especially in calculations of global illumination. Visibility determination, the process of deciding which surface can be seen from a certain point, has also problematic applications in biomedical engineering. The problem of visibility computation with mathematical tools can be presented as a visibility network. Instead of utilizing a 2D visibility network or graphs whose construction is well known, in this paper, a new method for the construction of 3D visibility graphs will be proposed. Drawing graphs as nodes connected by links in a 3D space is visually compelling but computationally difficult. Thus, the construction of 3D visibility graphs is highly complex and requires professional computers or supercomputers. A new method for optimizing the algorithm visibility network in a 3D space and a new method for quantifying the complexity of a network in DNA pattern recognition in biomedical engineering have been developed. Statistical methods have been used to calculate the topological properties of a visibility graph in pattern recognition. A new n-hyper hybrid method is also used for combining an intelligent neural network system for DNA pattern recognition with the topological properties of visibility networks of a 3D space and for evaluating its prospective use in the prediction of cancer.

Association of mir-196a-2 rs11614913 and mir-149 rs2292832 Polymorphisms With Risk of Cancer: An Updated Meta-Analysis

Background: Accumulating evidence suggests that functional dysregulations of miRNAs, especially miR-196a-2 and miR-149, in cancers could be attributed to polymorphisms in miRNA sequences. This study was aimed at clarifying the association of mir-196a-2 rs11614913 and mir-149 rs2292832 with cancer risk by performing an updated meta-analysis of genetic association studies. Methods: PubMed, Embase, Scopus, and ScienceDirect databases were searched until 9 April 2018 to identify eligible studies. Studies should meet the following criteria to be included in the meta-analysis: evaluation of genetic association between rs11614913 and/or rs2292832 and susceptibility to cancer; A case-control design; Written in English; Availability of sufficient data for estimating odds ratio (OR) and its 95% confidence interval (95%CI). Studies that met the following criteria were excluded: review articles, meta-analysis, abstracts or conference papers; duplicate publications; studies on animals or cell-lines; studies without a case-control design; studies that did not report genotype frequencies. Pooled ORs and 95% CIs were estimated using a total of 111 studies (41,673 cases and 49,570 controls) for mir-196a rs11614913 and 44 studies (15,954 cases and 19,594 controls) for mir-149 rs2292832. Stratified analysis according to quality scores, genotyping method, ethnicity, broad cancer category and cancer type was also performed. Results: Mir-196a-2 rs11614913 T allele was associated with decreased cancer risk in overall population. The association was only significant in Asians but not Caucasians. In subgroup analysis, significant associations were found in high quality studies, gynecological cancers, ovarian, breast, and hepatocellular cancer. Mir-149 rs2292832 was not associated with cancer risk in overall population and there were no differences between Asians and Caucasians. However, the T allele was associated with a decrease risk of gastrointestinal tract cancers under the heterozygote model and an increased risk of colorectal cancer under the recessive model. Conclusions: The present meta-analysis suggests that mir-196a-2 rs11614913 may contribute to the risk of cancer especially in Asians. Mir-149 rs2292832 may modulate the risk of gastrointestinal tract cancers especially colorectal cancer. This study had some limitations such as significant heterogeneity in most contrasts, limited number of studies enrolling Africans or Caucasians ancestry and lack of adjustment for covariates and environmental interactions.

Circular RNAs in Vascular Functions and Diseases

Vascular disease is one of the top five causes of death and affects a variety of other diseases, such as heart, nervous system, and metabolic disorders. Vascular dysfunction is a hallmark of ischemia, cancer, and inflammatory diseases and can accelerate the progression of diseases. Circular RNAs (circRNAs) are a new type of noncoding RNAs with covalent bond ring structure, which have been reported to be abnormally expressed in many human diseases. circRNAs regulate gene expression through the sponging of microRNAs (miRNAs) and can also be used as disease biomarkers. Here we will summarize the functions of circRNAs in vascular diseases, including vascular dysfunction, atherosclerosis, diabetes mellitus-related retinal vascular dysfunction, chronic thromboembolic pulmonary hypertension, carotid atherosclerotic disease, hepatic vascular invasion in hepatocellular carcinoma, aortic aneurysm, coronary artery disease, and type 2 diabetes mellitus.

Polymorphisms in non-coding RNAs and risk of colorectal cancer: A systematic review and meta-analysis

Colorectal cancer (CRC) has been regarded as a common cancer due to its prevailing incidence in both males and females. Recently, non-coding RNAs used as biomarkers for screening, diagnosis and prognosis of different cancers have been under the focus of attention. As a result of this, the aim of this study was to systematically review articles that investigated the SNPs in genes related to microRNAs and long non-coding RNAs to assess the genetic susceptibility of colorectal cancer risk. The outcome is presented as the results of a meta-analysis. We systematically searched PubMed, Web of Science, and Scopus to identify relevant studies published up to 20/5/2017. These included eligible studies consisting of 23,581 patients and 22,697 controls. The conferred risk was estimated and presented using odds ratios (ORs) and 95% confidence intervals (CI). The Hardy-Weinberg equilibrium (HWE) was assessed by the goodness-of-fit chi-square test in all studies. The power of each study was also calculated based on the available results. Out of 27 different microRNAs which had published results, although most of the studies were under powered, miR-146a and miR-196a were amongst the most studied microRNAs. For five miRNAs (miR-196a, miR-146a, miR-27a, miR-499 and miR-149) which we performed a meta-analysis, miR-27a and miR-149 gene polymorphisms were associated with susceptibility to CRC. Other miRNAs did not show any effect on the CRC risk. Overall, significant association between miR-149 rs2292832 and susceptibility to cancer was identified in a recessive genetic model, TT/ (TC + CC) (OR = 1.19, 95% CI = 1.02-1.39, P = 0.02). On the other hand, rs895819 (miR-27a) GG carriers were more susceptible to CRC (OR = 1.47, 95% CI = 1.21-1.78, P = <0.05) in a recessive genetic model. Analysis of the data based on race revealed that rs2910164 (miR-146a) polymorphism may decrease the risk of CRC among Europeans, in a co dominant model [OR = 0.81, 95% CI 0.66-0.99, p = 0.04], but not among Asians. In conclusion, certain miRNAs (miR-27a and miR-149) may affect the CRC risk and can be regarded as genetic markers amongst different populations. LncRNAs still have to be studied more to reach a conclusion for their association with CRC risk.

MicroRNAs as non-invasive diagnostic biomarkers for gastric cancer: Current insights and future perspectives

Non-invasive diagnostic biomarkers may contribute to an early identification of gastric cancer (GC) and improve the clinical management. Unfortunately, no sensitive and specific screening biomarkers are available yet and the currently available approaches are limited by the nature of the disease. GC is a heterogenic disease with various distinct genetic and epigenetic events that occur during the multifactorial cascade of carcinogenesis. MicroRNAs (miRNAs) are commonly deregulated in gastric mucosa during the Helicobacter pylori infection and in stepwise manner from chronic gastritis, through preneoplastic conditions such as atrophic gastritis and intestinal metaplasia, to early dysplasia and invasive cancer. Identification of miRNAs in blood in 2008 led to a great interest on miRNA-based diagnostic, prognostic biomarkers in GC. In this review, we provide the most recent systematic review on the existing studies related to miRNAs as diagnostic biomarkers for GC. Here, we systematically evaluate 75 studies related to differential expression of circulating miRNAs in GC patients and provide novel view on various heterogenic aspects of the existing data and summarize the methodological differences. Finally, we highlight several important aspects crucial to improve the future translational and clinical research in the field.

No Association Between MicroRNA-608 rs4919510 G>C Polymorphism and Digestive System Cancers Susceptibility: A Meta-Analysis Based on 10,836 Individuals

Previous epidemiologic studies have revealed a possible association between microRNA-608 rs4919510 G>C polymorphism and digestive system cancers (DSCs) risk, but the results were not consistent. We therefore performed an updated meta-analysis to explore the association between microRNA-608 rs4919510 G>C polymorphism and DSCs risk. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the relationship between the microRNA-608 rs4919510 G>C polymorphism and DSCs risk. Heterogeneity, cumulative analyses, sensitivity analyses, and publication bias were also conducted to examine the statistical power. Eight published articles with nine independent case-control studies involving 10,836 individuals were included in this meta-analysis. Overall, no significant association was found between microRNA-608 rs4919510 G>C polymorphism and DSCs risk in general populations. But some significant protective effects were observed in the subgroup of Caucasian population group in three genetic models (C vs. G: OR = 0.82, 95% CI, 0.68–0.99, P = 0.03, I² = 0%; CC vs. GG: OR = 0.59, 95% CI = 0.36–0.97, P = 0.04, I² = 0%; GC+CC vs. GG: OR = 0.61, 95% CI = 0.37–0.99, P = 0.05, I² = 0%). In summary, current evidence indicates that the microRNA-608 rs4919510 G>C polymorphism maybe an important factor of DSCs susceptibility, especially in Caucasian population.

The role of microRNA-608 polymorphism on the susceptibility and survival of cancer: a meta-analysis

The role of rs4919510 polymorphism in microRNA-608 (miR-608) and cancer susceptibility and prognosis remain controversial and debatable. We conducted a meta-analysis of twenty-four eligible publications on the association of rs4919510 polymorphism with cancer risk and/or prognosis. Odds ratios, hazard ratios, and 95% confidence interval were used to investigate the association between this polymorphism and susceptibility, overall survival, and recurrence-free survival of cancer. Overall, eighteen case-control studies and nine cohort studies evaluated the susceptibility and prognostic value of rs4919510 polymorphism in cancer, respectively. Pooled analysis showed that rs4919510 polymorphism was not associated with cancer risk in all five genetic models. When stratifying by different cancer sites, rs4919510 polymorphism was detected to have a significant association with a decreased risk of colorectal cancer in homozygous model (P = 0.006) and recessive model (P = 0.001), subgroup analysis also emerged a weakened correlation between rs4919510 polymorphism and an increased risk of papillary thyroid cancer in heterozygote model (P = 0.04). Furthermore, the prognosis of rs4919510 variant in cancer patients showed that rs4919510 GG genotype was significant association with poor recurrence-free survival in homozygous models (P = 0.04). The meta-analysis suggested that the microRNA-608 rs4919510 polymorphism maybe associate with a significantly decreased risk for colorectal cancer. Further investigations on larger populations are required to evaluate and confirm this relationship.

A Variant of COL3A1 (rs3134646) Is Associated With Risk of Developing Diverticulosis in White Men

BACKGROUND

Colonic diverticulosis is one of the most common gastroenterological disorders. Although diverticulosis is typically benign, many individuals develop diverticulitis or other aspects of diverticular disease. Diverticulosis is thought to stem from a complex interaction of environmental, dietary, and genetic factors; however, the contributing genetic factors remain unknown.

OBJECTIVE

The aim of our present study was to determine the role of genetic variants within genes encoding for collagens of the connective tissue in diverticulosis.

DESIGN

This was a transsectional genetic association study.

SETTINGS

This study was conducted at three tertiary referral centers in Germany and Lithuania.

PATIENTS

Single-nucleotide polymorphisms in COL3A1 (rs3134646, rs1800255) and COL1A1 (rs1800012) were genotyped in 422 patients with diverticulosis and 285 controls of white descent by using TaqMan assays.

MAIN OUTCOME MEASURES

The association of colonoscopy-proven diverticulosis with genetic polymorphisms with herniations was assessed in multivariate models.

RESULTS

The rs3134646, rs1800255, and rs1800012 variants were significantly associated with the risk of developing diverticulosis in the univariate model; however, these associations were not significant in the multivariate logistic regression analysis including additional nongenetic variables. When selectively analyzing sexes, the genotype AA (AA) in rs3134646 remained significantly associated with diverticulosis in men (OR, 1.82; 95% CI, 1.04-3.20; p = 0.04).

LIMITATIONS

Because a candidate approach was used, additional relevant variants could be missed. Within our cohort of patients with diverticulosis, only a small proportion had diverticular disease and thus, we could not examine the variants in these subgroups. Functional studies, including the analysis of the involved collagens, are also warranted.

CONCLUSIONS

Our study shows that a variant of COL3A1 (rs3134646) is associated with the risk of developing colonic diverticulosis in white men, whereas rs1800255 (COL3A1) and rs1800012 (COL1A1) were not associated with this condition after adjusting for confounding factors. Our data provide novel valuable insights in the genetic susceptibility to diverticulosis. See Video Abstract at http://links.lww.com/DCR/A504.

Association of two microRNA polymorphisms miR-27 rs895819 and miR-423 rs6505162 with the risk of cancer

Many studies have been conducted to investigate the association between miR-27 rs895819 A > G and miR-423 rs6505162 C > A and cancer risk; however, the results are not consistent. In order to acquire a more precise assessment of the correlation, we performed this meta-analysis. We searched PubMed, EMBASE and Web of Science databases to identify eligible studies. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were applied to evaluate the correlation of these two microRNA polymorphisms with cancer risk. Forty-five eligible studies from thirty-five articles were included in our analysis. The results showed that rs895819 was associated with a decreased cancer risk in Caucasians (AG vs. AA: OR = 0.87, 95% CI = 0.79-0.96; GG+AG vs. AA: OR = 0.89, 95% CI = 0.81-0.98). When grouped by ethnicity, an increased risk was observed in colorectal cancer (G vs. A: OR = 1.19, 95% CI = 1.08-1.32; GG vs. AA: OR = 1.58, 95% CI = 1.28-1.96; GG vs. AG+AA: OR = 1.58, 95% CI = 1.29-1.93), while a decreased risk was found in breast cancer (G vs. A: OR = 0.93, 95% CI = 0.87-0.99; GG+AG vs. AA: OR = 0.91, 95% CI = 0.83-0.99). For rs6505162, a significantly decreased cancer risk was observed in lung cancer under all five genetic models. To summarize, our results indicated that rs895819 was a protective factor for cancer in Caucasians and could increase colorectal cancer risk but decrease breast cancer risk. Moreover, rs6505162 was a protective factor for lung cancer.

Association of miR-608 rs4919510 polymorphism and cancer risk: a meta-analysis based on 13,664 subjects

Single nucleotide polymorphisms (SNPs) in MicroRNAs (miRNAs) are involved in the mechanism of carcinogenesis. Several studies have evaluated the association of rs4919510 SNP in miR-608 with cancer susceptibility in different types of cancer, with inconclusive outcomes. To obtain a more precise estimation, we carried out this meta-analysis through systematic retrieval from the PubMed and Embase database. A total of 10 case-control studies were analyzed with 6,000 cases and 7,664 controls. The results showed that 4919510 SNP in miR-608 was significantly associated with decreased cancer risk only in recessive model (CC vs. GG+GC: OR=0.89, 95% CI: 0.82-0.97, P=0.009). By further stratified analysis, we found that rs4919510 SNP had some relationship with decreased cancer risk in both homozygote model (CC vs. GG: OR=0.59, 95% CI: 0.36-0.96, P=0.034) and dominant model (CG+ CC vs. GG: OR=0.60, 95% CI: 0.37-0.98, P=0.042) in Caucasians but no relationship in any genetic model in Asians. These results indicated that miR-608 rs4919510 polymorphism may contribute to the decreased cancer susceptibility and could be a promising target to forecast cancer risk for clinical practice. However, to further confirm these results, well-designed large scale case-control studies are needed in the future.

rs11614913 polymorphism in miRNA-196a2 and cancer risk: an updated meta-analysis

Several epidemiological studies have reported that polymorphisms in microRNA-196a2 (miR-196a2) were associated with various cancers. However, the results remained unverified and were inconsistent in different cancers. Therefore, we carried out an updated meta-analysis to elaborate the effects of rs11614913 polymorphism on cancer susceptibility. A total of 84 articles with 35,802 cases and 41,541 controls were included to evaluate the association between the miR-196a2 rs11614913 and cancer risk by pooled odds ratios (ORs) and 95% confidence intervals (CIs). The results showed that miR-196a2 rs11614913 polymorphism is associated with cancer susceptibility, especially in lung cancer (homozygote comparison, OR =0.840, 95% CI =0.734-0.961; recessive model, OR =0.858, 95% CI =0.771-0.955), hepatocellular carcinoma (allelic contrast, OR =0.894, 95% CI =0.800-0.998; homozygote comparison, OR =0.900, 95% CI =0.813-0.997; recessive model, OR =0.800, 95% CI =0.678-0.944), and head and neck cancer (allelic contrast, OR =1.076, 95% CI =1.006-1.152; homozygote comparison, OR =1.214, 95% CI =1.043-1.413). In addition, significant association was found among Asian populations (allele model, OR =0.847, 95% CI =0.899-0.997, P=0.038; homozygote model, OR =0.878, 95% CI =0.788-0.977, P=0.017; recessive model, OR =0.895, 95% CI =0.824-0.972, P=0.008) but not in Caucasians. The updated meta-analysis confirmed the previous results that miR-196a2 rs11614913 polymorphism may serve as a risk factor for patients with cancers.

miR-146a C/G polymorphism increased the risk of head and neck cancer, but overall cancer risk: an analysis of 89 studies

Several studies have evaluated the association of miR-146a C/G with head and neck cancer (HNC) susceptibility, and overall cancer risk, but with inconclusive outcomes. To drive a more precise estimation, we carried out this meta-analysis. The literature was searched from MEDLINE (mainly PubMed), Embase, the Cochrane Library, and Google Scholar databases to identify eligible studies. A total of 89 studies were included. The results showed that miR-146a C/G was significantly associated with increased HNC risk in dominant model (I² =15.6%, P_{heterogeneity}=0.282, odds ratio (OR) =1.088, 95% confidence interval (CI) =1.002–1.182, P=0.044). However, no cancer risk was detected under all genetic models. By further stratified analysis, we found that rs4919510 mutation contributed to the risk of HNC amongst Asians under homozygote model (I² =0, P_{heterogeneity}=0.541, OR =1.189, 95% CI =1.025–1.378, P=0.022), and dominant model (I² =0, P_{heterogeneity}=0.959, OR =1.155, 95% CI =1.016–1.312, P=0.028). Simultaneously, in the stratified analysis by source of controls, a significantly increased cancer risk amongst population-based studies was found under homozygote model, dominant model, recessive model, and allele comparison model. However, no significant association was found in the stratified analysis by ethnicity and source of control. The results indicated that miR-146a C/G polymorphism may contribute to the increased HNC susceptibility and could be a promising target to forecast cancer risk for clinical practice. However, no significant association was found in subgroup analysis by ethnicity and source of control. To further confirm these results, well-designed large-scale case–control studies are needed in the future.

Small Molecules in Rare Tumors: Emerging Role of MicroRNAs in GIST

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of gastrointestinal tract. GISTs have very different clinical phenotypes and underlying molecular characteristics that are not yet completely understood. microRNAs (miRNAs) have been shown to participate in carcinogenesis pathways through post-transcriptional regulation of gene expression in different tumors. Over the last years emerging evidence has highlighted the role of miRNAs in GISTs. This review provides an overview of original research papers that analyze miRNA deregulation patterns, functional role, diagnostic, therapeutic and prognostic implications in GIST as well as provides directions for further research in the field.

Systematic evaluation of cancer risk associated with rs2292832 in miR‑149 and rs895819 in miR‑27a: a comprehensive and updated meta‑analysis

The aim of this study is to provide a precise quantification for the association between miR-149 T > C (rs2292832) and miR-27a A > G (rs895819) and the risk of cancer. We conducted a systematic literature review and evaluated the quality of included studies based on Newcastle-Ottawa Scale (NOS). Pooled odds ratios (ORs) and corresponding 95% confidence intervals (95% CIs) were calculated to assess the strengths of the associations. We identified 40 studies for pooled analyses. Overall, the results demonstrated that the rs2292832 polymorphism was subtly decrease the risk of breast cancer (CT + CC vs TT: OR = 0.83, 95% CI: 0.70-0.98, P = 0.03; CC vs CT + TT: OR = 0.80, 95% CI: 0.68-0.93, P = 0.00), and the rs895819 polymorphism wasassociated with significantly increased cancer risk in the Asian population (AG + GG vs AA: OR = 1.24, 95% CI: 1.03-1.50, P = 0.02) and in colorectal cancer subgroup (GG vs AA: OR = 1.45, 95% CI: 1.10-1.92, P = 0.00; AG + GG vs AA: OR = 1.35, 95% CI: 1.15-1.58, P = 0.00; GG vs AG + AA: OR = 1.36, 95% CI: 1.04-1.77, P = 0.02). In addition, a subtly decreased risk was observed in the Caucasian population and in breast cancer subgroup. In conclusion, the rs2292832 polymorphism was significantly associated with increased breast cancer risk, and the rs895819 polymorphism contributes to the susceptibility of colorectal and breast cancer.

Association between polymorphisms of TAS2R16 and susceptibility to colorectal cancer

BACKGROUND

Genetics plays an important role in the susceptibility to sporadic colorectal cancer (CRC). In the last 10 years genome-wide association studies (GWAS) have identified over 40 independent low penetrance polymorphic variants. However, these loci only explain around 1‑4% of CRC heritability, highlighting the dire need of identifying novel risk loci. In this study, we focused our attention on the genetic variability of the TAS2R16 gene, encoding for one of the bitter taste receptors that selectively binds to salicin, a natural antipyretic that resembles aspirin. Given the importance of inflammation in CRC, we tested whether polymorphic variants in this gene could affect the risk of developing this neoplasia hypothesizing a role of TAS2R16 in modulating chronic inflammation within the gut.

METHODS

We performed an association study using 6 tagging SNPs, (rs860170, rs978739, rs1357949, rs1525489, rs6466849, rs10268496) that cover all TAS2R16 genetic variability. The study was carried out on 1902 CRC cases and 1532 control individuals from four European countries.

RESULTS

We did not find any statistically significant association between risk of developing CRC and selected SNPs. However, after stratification by histology (colon vs. rectum) we found that rs1525489 was associated with increased risk of rectal cancer with a (P_trend of = 0.0071).

CONCLUSIONS

Our data suggest that polymorphisms within TAS2R16 gene do not have a strong influence on colon cancer susceptibility, but a possible role in rectal cancer should be further evaluated in larger cohorts.

Polymorphisms in Non-coding RNA Genes and Their Targets Sites as Risk Factors of Sporadic Colorectal Cancer

Colorectal cancer (CRC) is a complex disease that develops as a consequence of both genetic and environmental risk factors in interplay with epigenetic mechanisms, such as microRNAs (miRNAs). CRC cases are predominantly sporadic in which the disease develops with no apparent hereditary syndrome. The last decade has seen the progress of genome-wide association studies (GWAS) that allowed the discovery of several genetic regions and variants associated with weak effects on sporadic CRC. Collectively these variants may enable a more accurate prediction of an individual's risk to the disease and its prognosis. However, the number of variants contributing to CRC is still not fully explored.SNPs in genes encoding the miRNA sequence or in 3'UTR regions of the corresponding binding sites may affect miRNA transcription, miRNA processing, and/or the fidelity of the miRNA-mRNA interaction. These variants could plausibly impact miRNA expression and target mRNA translation into proteins critical for cellular integrity, differentiation, and proliferation.In the present chapter, we describe the different aspects of variations related to miRNAs and other non-coding RNAs (ncRNAs) and evidence from studies investigating these candidate genetic alterations in support to their role in CRC development and progression.

Polymorphisms of microRNA target genes IL12B, INSR, CCND1 and IL10 in gastric cancer

AIM

To evaluate associations between miRNA target genes IL12B, INSR, CCND1 and IL10 polymorphisms and gastric cancer (GC) in European population.

METHODS

Gene polymorphisms were analyzed in 508 controls and 474 GC patients from 3 tertiary centers in Germany, Lithuania and Latvia. Controls were patients from the out-patient departments, who were referred for upper endoscopy because of dyspeptic symptoms and had no history of previous malignancy. Gastric cancer (GC) patients had histopathological verification of gastric adenocarcinoma. Genomic DNA was extracted using salting out method from peripheral blood mononuclear cells. IL12B T>G (rs1368439), INSR T>C (rs1051690), CCND1 A>C (rs7177) and IL10 T>C (rs3024498) SNPs were genotyped by the real-time polymerase chain reaction. Associations between gene polymorphism and GC were evaluated using multiple logistic regression analysis with adjustment for sex, age and country of birth.

RESULTS

We observed similar distribution of genotypes and allelic frequencies of all polymorphisms between GC patients and controls except of INSR rs1051690. The frequency of the T allele of INSR gene was significantly higher in GC patients than in controls (23.26% and 19.19% respectively, P = 0.028). CT genotype was also more prevalent in patients compared to control group (38.48% and 30.12% respectively, P < 0.021). Logistic regression analysis revealed that only one polymorphism (rs1051690 in INSR gene) was associated with increased risk of GC. Carriers of CT genotype had higher odds of GC when compared to CC genotype (OR = 1.45, 95%PI: 1.08-1.95, P = 0.01). Similar association was observed in a dominant model for INSR gene, where comparison of TT+CT vs CC genotypes showed an increased risk of GC (OR = 1.44, 95%PI: 1.08-1.90, P = 0.01). Other analyzed SNPs were not associated with the presence of GC.

CONCLUSION

INSR rs1051690 SNP is associated with increased risk of GC, while polymorphisms in IL12B, CCND1 and IL10 genes are not linked with the presence of GC.

Germline miRNA DNA variants and the risk of colorectal cancer by subtype

MicroRNAs (miRNAs) regulate up to one-third of all protein-coding genes including genes relevant to cancer. Variants within miRNAs have been reported to be associated with prognosis, survival, response to chemotherapy across cancer types, in vitro parameters of cell growth, and altered risks for development of cancer. Five miRNA variants have been reported to be associated with risk for development of colorectal cancer (CRC). In this study, we evaluated germline genetic variation in 1,123 miRNAs in 899 individuals with CRCs categorized by clinical subtypes and in 204 controls. The role of common miRNA variation in CRC was investigated using single variant and miRNA-level association tests. Twenty-nine miRNAs and 30 variants exhibited some marginal association with CRC in at least one subtype of CRC. Previously reported associations were not confirmed (n = 4) or could not be evaluated (n = 1). The variants noted for the CRCs with deficient mismatch repair showed little overlap with the variants noted for CRCs with proficient mismatch repair, consistent with our evolving understanding of the distinct biology underlying these two groups. © 2016 The Authors Genes, Chromosomes & Cancer Published by Wiley Periodicals, Inc.

Thrombosis Related ABO, F5, MTHFR, and FGG Gene Polymorphisms in Morbidly Obese Patients

Objective. Obesity is a well-known risk factor for thrombotic complications. The aim of the present study was to determine the frequency of thrombosis related ABO, F5, MTHFR, and FGG gene polymorphisms in morbidly obese patients and compare them with the group of nonobese individuals. Methods. Gene polymorphisms were analyzed in 320 morbidly obese patients (BMI > 40 kg/m²) and 303 control individuals (BMI < 30 kg/m²) of European descent. ABO C>T (rs505922), F5 C>G (rs6427196), MTHFR C>T (rs1801133), and FGG C>T (rs6536024) SNPs were genotyped by RT-PCR. Results. We observed a tendency for MTHFR rs1801133 TT genotype to be linked with morbid obesity when compared to CC genotype; however, the difference did not reach the significant P value (OR 1.84, 95% CI 0.83–4.05, P = 0.129). Overall, the genotypes and alleles of rs505922, rs6427196, rs1801133, and rs6536024 SNPs had similar distribution between morbidly obese and nonobese control individuals. Distribution of height and weight means among individuals carrying different rs505922, rs6427196, rs1801133, and rs6536024 genotypes did not differ significantly. Conclusions. Gene polymorphisms ABO C>T (rs505922), F5 C>G (rs6427196), MTHFR C>T (rs1801133), and FGG C>T (rs6536024) were not associated with height, weight, or morbid obesity among European subjects.

MiR-608, pre-miR-124-1 and pre-miR26a-1 polymorphisms modify susceptibility and recurrence-free survival in surgically resected CRC individuals

Genetic variation within microRNA (miRNA) may result in its abnormal folding or aberrant expression, contributing to colorectal turmorigenesis and metastasis. However, the association of six polymorphisms (miR-608 rs4919510, miR-499a rs3746444, miR-146a rs2910164, pre-miR-143 rs41291957, pre-miR-124-1 rs531564 and pre-miR-26a-1 rs7372209) with colorectal cancer (CRC) risk, therapeutic response and survival remains unclear. A retrospective study was carried out to investigate the association in 1358 0-III stage resected CRC patients and 1079 healthy controls using Sequenom's MassARRAY platform. The results showed that rs4919510 was significantly associated with a decreased susceptibility to CRC in co-dominant, allele and recessive genetic models, and the protective role of rs4919510 allele G and genotype GG was more pronounced among stage 0-II cases; significant association between rs531564 and poor RFS was observed in cases undergoing adjuvant chemo-radiotherapy in co-dominant, allele and dominant models; moreover, there was a positive association between rs7372209 and recurrence-free survival in stage II cases in co-dominant and over-dominant models; additionally, a cumulative effect of rs531564 and rs7372209 at-risk genotypes with hazard ratio at 1.30 and 1.95 for one and two at-risk genotypes was examined in stage II cases, respectively. Our findings indicated that rs4919510 allele G and genotype GG were protective factors for 0-II stage CRC, rs7372209 and rs531564 could decrease RFS in II stage individuals and resected CRC patients receiving adjuvant chemo-radiology.

Risk Factors for Sporadic Pancreatic Neuroendocrine Tumors: A Case-Control Study

The current study examined risk factors for sporadic pancreatic neuroendocrine tumors (PNETs), including smoking, alcohol use, first-degree family history of any cancer (FHC), and diabetes in the Han Chinese ethnic group. In this clinic-based case-control analysis on 385 patients with sporadic PNETs and 614 age- and sex-matched controls, we interviewed subjects using a specific questionnaire on demographics and potential risk factors. An unconditional multivariable logistic regression analysis was used to estimate adjusted odds ratios (AORs). No significant differences were found between patients and controls in terms of demographic variables. Most of the patients with PNETs had well-differentiated PNETs (G1, 62.9%) and non-advanced European Neuroendocrine Tumor Society (ENETS) stage (stage I or II, 83.9%). Ever/heavy smoking, a history of diabetes and a first-degree FHC were independent risk factors for non-functional PNETs. Only heavy drinking was found to be an independent risk factor for functional PNETs (AOR = 1.87; 95% confidence interval [CI], 1.01–3.51). Ever/heavy smoking was also associated with advanced ENETS staging (stage III or IV) at the time of diagnosis. This study identified first-degree FHC, ever/heavy smoking, and diabetes as risk factors for non-functional PNETs, while heavy drinking as a risk factor for functional PNETs.

Association of the miR-146a rs2910164 polymorphism with gastric cancer susceptibility and prognosis

Aim: Single nucleotide polymorphisms in miRNA-coding region may be involved in the development or progression of gastric cancer (GC). Materials & methods: Six SNPs (miR-146a rs2910164, miR-196a2 rs11614913, miR-27a rs895819, miR-423 rs6505162, miR-608 rs4919510, miR-149 rs2292832) were genotyped in 898 histologically confirmed GC cases and 992 controls in this hospital-based case–control study. Results: The G/G genotype of rs2910164 was associated with reduced risk of GC (odds ratio: 0.76, 95% CI: 0.60–0.97; p = 0.024). Meanwhile, in 838 GC cases receiving radical tumorectomy, cases bearing the G/G genotype of rs2910164 had shorter survival time comparing to cases with C/C or C/G genotype (hazard ratio: 1.36, 95% CI: 1.04–1.78, p = 0.023). Conclusion: rs2910164 of miR-146a is associated with GC.

Association between microRNA-27a rs895819 polymorphism and risk of colorectal cancer: A meta-analysis

Colorectal cancer (CRC) is the most common malignancy in the human digestive system. Previous results regarding the association between microRNA-27a rs895819 polymorphisms and CRC risk are controversial. We therefore performed a meta-analysis of seven studies totaling 2230 cases and 2775 controls to systematically evaluate this association. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were obtained using a fixed-effects model. A moderate evidence for the association between mir-27a polymorphism and CRC risk was found under multiple genetic models (dominant model: OR = 1.15, 95% CI: 1.02-1.29, p = 0.02; recessive model: OR = 1.49, 95% CI: 1.27-1.76, p <0.001; homozygote model: OR = 1.53, 95% CI: 1.28-1.83, p <0.001; allele model: OR = 1.21, 95% CI: 1.11-1.31, p <0.001). Subgroup analysis showed a significant association between mir-27a rs895819 polymorphism and CRC risk among Chinese populations. On the contrary, we found no evidence of association among Caucasian populations due to small samples (p > 0.05). In conclusion, this meta-analysis suggested that rs895819 polymorphism in mir-27a may be a potential genetic risk factor for CRC, particularly in Chinese populations.

MicroRNA variants as genetic determinants of bone mass

Single nucleotide polymorphisms (SNPs) are the most abundant genetic variants that contribute to the heritability of bone mass. MicroRNAs (miRNAs, miRs) are key post-transcriptional regulators that modulate the differentiation and function of skeletal cells by targeting multiple genes in the same or distinct signaling pathways. SNPs in miRNA genes and miRNA binding sites can alter miRNA abundance and mRNA targeting. This review describes the potential impact of miRNA-related SNPs on skeletal phenotype. Although many associations between SNPs and bone mass have been described, this review is limited to gene variants for which a function has been experimentally validated. SNPs in miRNA genes (miR-SNPs) that impair miRNA processing and alter the abundance of mature miRNA are discussed for miR-146a, miR-125a, miR-196a, miR-149 and miR-27a. SNPs in miRNA targeting sites (miR-TS-SNPs) that alter miRNA binding are described for the bone remodeling genes bone morphogenetic protein receptor 1 (Bmpr1), fibroblast growth factor 2 (Fgf2), osteonectin (Sparc) and histone deacetylase 5 (Hdac5). The review highlights two aspects of miRNA-associated SNPs: the mechanism for altering miRNA mediated gene regulation and the potential of miR-associated SNPs to alter osteoblast, osteoclast or chondrocyte differentiation and function. Given the polygenic nature of skeletal diseases like osteoporosis and osteoarthritis, validating the function of additional miRNA-associated SNPs has the potential to enhance our understanding of the genetic determinants of bone mass and predisposition to selected skeletal diseases.

Association between pre-miR-27a functional polymorphism and risk of colorectal cancer in north Chinese Han population

MicroRNA-27a (miR-27a) is deemed as an oncogene in malignancies including colorectal cancer (CRC), and rs895819 within pre-miR-27a may affect its secondary structure, leading to its aberrant expression and dysfunction of its targeted gene. We investigated genotype and allele frequencies of the locus in 412 I–III stage CRC cases and 412 age- and sex-matched healthy individuals to explore the possible association between them in the north of Chinese population. The results showed that frequencies of alleles A and G and genotypes GG, AG, and AA of the locus were 65.7%, 34.3%, 17.0%, 34.7%, and 48.3% in cases and 69.9%, 30.1%, 9.9%, 40.2%, and 49.8% in controls, respectively. GG genotype of the locus was positively associated with an increased risk of CRC in codominant (P=0.01, adjusted odds ratio =1.541, 95% confidence interval =1.110–2.239 for genotype GG vs AA) and recessive (P=0.003, adjusted odds ratio =1.855, 95% confidence interval =1.221–2.786 for genotype GG vs AA/GA) models, indicating that GG genotype of the locus might increase susceptibility to CRC. Moreover, genotypes AG and GG and allele G were significantly associated with III stage (P<0.001, P<0.001, and P=0.001, respectively), suggesting that the locus was associated with the progression of CRC. These results suggested that rs895819 within pre-miR-27a was involved in colorectal carcinogenesis and progression, genotype GG of the locus might be a susceptible factor for CRC, and allele G and allele G carrier (genotypes AG and GG) could predict CRC progression in north Chinese Han population.

Genotype GG of rs895819 Functional Polymorphism Within miR-27a Might Increase Genetic Susceptibility to Colorectal Cancer in Han Chinese Population

BACKGROUND

MicroRNA-27a (miR-27a) is supposed to be an oncogene in various types of cancers, and genetic variation of miR-27a might result in aberrant expression and abnormal second structure of mature-miR-27a, contributing to elevated genetic risk and poor prognosis for colorectal cancer (CRC).

METHODS

In order to explore the possible association between rs895819 within miR-27a and CRC in Han Chinese population, we investigated the genotype distributions of rs895819 in 508 CRC cases and 562 healthy check-up controls using TaqMan genotype discrimination system, and analyzed the possible association between them. Odds ratio (OR) and 95% confidential interval (95% CI) were used to assess the strength between allele and genotype of the locus and risk of CRC.

RESULTS

In our study, we found that genotype GG of rs895819 was significantly associated with an increased risk for CRC (17.1% vs. 11.6%, adjusted OR = 1.546, 95% CI = 1.070-2.236), and allele A carrier (AA/AG) was significantly associated with a decreased risk for CRC (82.9% vs. 89.4%, adjusted OR = 0.63, 95% CI = 0.446-0.893). In addition, a significant association was observed between genotype GG and larger tumor size (>5 cm; P < 0.001), and allele G was significantly associated with higher pathological stage (TNM-III) (P = 0.008).

CONCLUSION

These results indicated that miR-27a might be involved in the development and progression of CRC, genotype GG within rs895819 might be a genetic susceptible factor for CRC. Further multicentral, large sample size, and well-designed epidemiological study as well as functional study are warrant to verify our findings.