A functional polymorphism in MIR196A2 is associated with risk and prognosis of gastric cancer

miR-155 rs767649 T>A gene polymorphism is associated with downregulation of miR-155 expression, suppressor of cytokine signaling-1 overexpression, and low probability of metastatic tumor at the time of breast cancer diagnosis

Background

MicroRNA-155 is a key player in inflammatory reactions, carcinogenesis, and tumor development. In this study, polymorphism of miRNA-155 rs767649 T>A and its gene and suppressor of cytokine signaling-1 (SOCS-1) expression were investigated in relation to cancer susceptibility and development in breast cancer (BC) patients.

Materials and Methods

Polymorphism of miRNA-155 rs767649 T>A was evaluated between a population of 174 patients with BC and 129 controls using restriction fragment length polymorphism and the expression of miR-155 and SOCS-1 were examined in peripheral blood mononuclear cells (PBMCs) by real-time polymerase chain reaction.

Results

TT genotype of miR-155 rs767649 T>A was associated with higher level of miR-155 in PBMCs of BC patients relative to AT and AA genotypes (21.76 ± 4.4, 4.046 ± 1.35, 2.56 ± 0.81, respectively; P < 0.001) and increased lymph node metastasis (r = 0.292, P = 0.001), not BC susceptibility (P = 0.402 and P = 0.535; respectively). TT genotype of miR-155 rs767649 T>A was associated with less gene expression of SOCS-1 in PBMCs of BC patients compared to AT and AA genotypes (1.173 ± 0.57, 0.92 ± 0.827, 5.512 ± 0.92, respectively; P = 0.003).

Conclusion

This study demonstrated for the first time the association between the T allele of the rs767649 T>A polymorphism in the pre-MIR155 gene and higher expression of miR-155, lower expression of SOCS-1, and swift latent progression in newly diagnosed BC patients. Thus, miR-155 may play a critical role in BC pathogenesis.

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.

The Hippo signaling effector WWTR1 is a metastatic biomarker of gastric cardia adenocarcinoma

Background

Gastric cardia adenocarcinoma (GCA) is an aggressive subtype of gastric cancer with a high metastatic rate. However, the metastatic biomarker of GCA has not been established.

Methods

To search for the biomarker for GCA metastasis, we here examined expression of the Hippo signaling effector WWTR1 (WW domain containing transcription regulator 1, commonly listed as TAZ) in tumor tissue samples from 214 GCA cases using the tissue microarray assay (TMA), and statistically analyzed association of the WWTR1 expression with metastasis-related pathological outcomes and cumulative survival of the GCA patients. Furthermore, shRNA knockdown was used to determine the role of WWTR1 in promoting cell migration in gastric cancer cells.

Results

The results have shown that WWTR1 is overexpressed in 66.4% of the GCA tumor samples. Expression of WWTR1 has a significant inverse correlation with cumulative survival of GCA patients (p < 0.01). WWTR1 positive patients had a mean survival of 56.9 ± 4.4 months, comparing to WWTR1 negative mean survival of 77.3 ± 5.9 months. More importantly, expression of WWTR1 significantly associated with tumor invasion and metastasis (in T stage, p = 0.031; N stage, p < 0.01; and TNM stage, p < 0.001). Furthermore, knockdown of WWTR1 impaired migration of gastric cancer AGS cells.

Conclusions

Our studies have identified WWTR1 as a metastatic biomarker of GCA for poor prognosis, defined a role of WWTR1 in driving metastasis of gastric cancer, and suggested WWTR1 as a potential target for anti-metastatic therapy of GCA.

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.

MiRNA Polymorphisms and Cancer Prognosis: A Systematic Review and Meta-Analysis

Background: Accumulating studies have focused on the relationship between miRNAs polymorphisms and cancer prognosis. However, the results are conflicting and unconvincing. This systematic review and meta-analysis was conducted to explore the relationship between miRNAs polymorphisms and cancer prognosis, aiming to seek for markers with cancer prognostic function.

Methods: Hazard ratio of overall survival, disease-free survival (DFS) and recurrence-free survival were calculated to evaluate the association between miRNAs polymorphisms and cancer prognosis by using Stata software 11.0.

Results: We systematically reviewed the association of 17 miRNAs SNPs with cancer prognosis including 24,721 samples. It was shown that 6 miRNAs SNPs (miR-608 rs4919510, miR-492 rs2289030, miR-378 rs1076064, miR-499 rs4919510, miR-149 rs2292832, miR-196a2 rs11614913) were associated with better cancer overall survival (OS) while let-7i rs10877887 was associated with poor OS; the homozygous and heterozygote genotype of miR-423 were related to poor cancer relapse-free survival (RFS) when compared with the wild genotype; miR-146 rs2910164 was linked to favorable cancer DFS while miR-196a2 rs11614913 was associated with poor DFS.

Conclusions: In summary, let-7i rs10877887, miR-608 rs4919510, miR-492 rs2289030, miR-378 rs1076064, miR-423 rs6505162, miR-499 rs4919510, miR-149 rs2292832, miR-146 rs2910164, and miR-196a2 rs11614913 might serve as potential biomarkers for cancer prognosis.

Association of miRNA-146a rs2910164 and miRNA-196 rs11614913 polymorphisms in patients with ulcerative colitis: A meta-analysis and review

BACKGROUND

It has been reported that the single nucleotide polymorphisms (SNPs) miRNA-196 (miR-196) rs11614913 and miRNA-146a (miR-146a) rs2910164 are related to susceptibility to ulcerative colitis (UC). Because the previously reported results have been mixed and uncertain, the aim of this study was to perform a meta-analysis and review to assess the relationship between these 2 SNPs and UC risk.

METHODS

In this analysis, 5 studies involving 1023 cases and 1769 controls for miR-196 rs11614913 and 4 studies involving 827 cases and 1451 controls for miR-146 rs2910164 were included. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were used to pool the effect size.

RESULTS

A decreased risk of UC was identified in homozygote comparison (GG vs CC: OR = 0.69, 95% CI: 0.52-0.93, P = .02), recessive comparison (GG vs CG + CC: OR = 0.74, 95% CI: 0.59-0.92, P = .007), and dominant comparison (GG + CG vs CC: OR = 0.79, 95% CI: 0.65-0.97, P = .02) of miR-146 rs2910164 in Asian but not Caucasian population. No evidence of an association was shown between the rs11614913 polymorphism and UC risk in allelic, heterozygote, homozygote, recessive, and dominant models in both Caucasian and Asian populations (P > .05).

CONCLUSIONS

MiR-146 rs2910164, but not miR-196 rs11614913, was associated with a decreased risk of UC in Asian population. However, the results should be treated with caution because of the limited sample size and heterogeneity. Well-designed studies with large sample sizes and more ethnic groups are needed to validate the risks identified in the current meta-analysis and review.

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.

CYR61 (CCN1) is a metastatic biomarker of gastric cardia adenocarcinoma

Gastric cardia adenocarcinoma (GCA) is the most aggressive subtype of gastric cancer with a high metastatic rate. In this report, we collected tumor tissue samples from 214 GCA cases and examined expression of CYR61, a target gene product of the Hippo-YAP/TAZ pathway, in the GCA tumors by immunohistochemical (IHC) staining using the tissue microarray assay (TMA). The results have shown that CYR61 is overexpressed in 44% of the GCA tumor samples. Expression of CYR61 is inversely correlated with cumulative survival of GCA patients (p<0.001) and significantly associated only with metastatic pathological categories (with N category, p=0.052; with TNM stage, p=0.001). Furthermore, knockdown of CYR61 in gastric cancer AGS cells impairs the cancer cell migration and invasion, suggesting a driver role of CYR61 in metastasis. Thus, our studies have established CYR61 as a metastatic biomarker for prediction of poor prognosis of GCA and provided a potential molecular target for anti-metastatic therapy of GCA.

Polymorphisms in MIR122, MIR196A2, and MIR124A Genes are Associated with Clinical Phenotypes in Inflammatory Bowel Diseases

BACKGROUND

Inflammatory bowel diseases (IBDs), including Crohn's disease (CD) and ulcerative colitis (UC), are multifactorial disorders that result from a dysregulated inflammatory response to environmental factors in genetically predisposed individuals. Recently, microRNAs (miRNAs) have been shown to be involved in the development of IBDs.

AIMS

We investigated common variants in five miRNA genes in a cohort of Italian IBD patients, to evaluate their possible role in the disease's susceptibility and phenotype manifestations.

METHODS

The analysis included 267 CD patients, 207 UC patients, and 298 matched healthy controls. Polymorphisms in the MIR122, MIR499, MIR146A, MIR196A2, and MIR124A genes were evaluated by allelic discrimination assay.

RESULTS

We did not find associations between mir polymorphisms and IBD susceptibility. In both diseases, rs17669 and rs11614913 (MIR122 and MIR196A2) seem to contribute to clinical phenotypes: ileal location in CD (odds ratio [OR] = 1.82, p = 0.03; OR = 0.51, p = 0.01), and left-sided extent in UC (OR = 0.43, p = 0.05; OR = 0.28, p = 0.002). In CD, the MIR124A polymorphism (rs531564) contributed to colon location (p = 0.03, OR = 2.74). Finally, the variant allele of rs11614913 was associated with early age at onset in both diseases (p = 0.05 and p = 0.02).

CONCLUSIONS

We showed for the first time that polymorphisms in MIR122, MIR196A2, and MIR124A could play a role in clinical phenotype modulation in IBD.

The role of microRNA-196a in tumorigenesis, tumor progression, and prognosis

MicroRNAs are a large group of non-coding RNAs that have emerged as regulators of various biological processes, especially carcinogenesis and cancer progression. Recent evidence has shown that microRNA-196a (miR-196a) is upregulated in most types of tumors and involved in multiple biological processes via translational inhibition and mRNA cleavage, such as cell proliferation, migration, and invasion, mostly functioning as an oncogene. Dysregulation of miR-196a promotes oncogenesis and tumor progression. In this review, we summarize the upstream regulators, target genes, signaling pathways, and single nucleotide polymorphisms of miR-196a, which collectively affect cell proliferation, migration, and invasion. In addition, we review the clinical outcomes and significance of miR-196a. miR-196a may serve as a novel biomarker or target for diagnosis, prognosis, and therapy in several human cancers.

A risk of digestive tract neoplasms susceptibility in miR-146a and miR-196a2

Genome-wide association studies have identified many genes associated with digestive tract neoplasms. However, the published findings have been conflicting. The aim of our study was to evaluate the involvement of two polymorphisms (miR-146a rs2910164, miR-196a2 rs11614913) in digestive tract neoplasms risk and explore how miR-146a and miR-196a2 influence this risk. Systemic research of the PubMed, EBSCO, CBM and VIP databases was performed. The software STATA 12.0 was used to calculate odd ratios and 95% confidence intervals. There were 14 studies (6,053 cases and 6,527 controls) available for rs2910164 and 15 studies (5,648 cases and 6,607 controls) involved in rs11614913. Rs2910164G>C was statistically significantly associated with digestive tract neoplasms (OR 1.134, 95% CI 1.076-1.194, P < 0.001). In the subgroup analysis by ethnicity, significant association was observed in Asian individuals (OR 1.145, 95% CI 1.084-1.209, P < 0.001). We found a correlation between rs11614913 and only colorectal cancer (OR 1.325, 95% CI 1.102-1.594, P = 0.003). This study suggested that digestive tract neoplasms might associate with miR-146a variants, but not miR-196a2 variants.

Functional genetic variants in pre-miR-146a and 196a2 genes are associated with risk of lung cancer in North Indians

Objective: To find the association of two pre-miRNA polymorphisms with risk of lung cancer in North Indians. Materials & methods: Genotyping of 250 cases and 255 controls for miR-146a and miR-196a2 using PCR-RFLP. Results: Heterozygous subjects showed a risk toward lung cancer (LC), especially for adenocarcinoma (OR: 1.82; 95% CI: 1.04–3.20; p = 0.03) in miR-146a gene. TT genotype for miR-196a2 gene also showed 3.2-fold risk toward LC and the risk was fivefold higher for squamous cell carcinoma. Survival rate was significantly lower in subjects with TT genotype as compared with the CC genotype in miR-196a2. Conclusion: Both the single nucleotide polymorphism variants showed a positive association toward risk of lung cancer.

Associations of Polymorphisms in mir-196a2, mir-146a and mir-149 with Colorectal Cancer Risk: A Meta-Analysis

MicroRNAs (miRNAs) are non-coding RNAs which act as tumor suppressors or oncogenes. And single nucleotide polymorphism (SNP) in miRNA regions is one type of genetic variations in human genome. Various studies have investigated the associations of miRNAs SNP and kinds of cancers. In this article, we searched eligible studies to explore the relationships between mir-196a2 /mir-146a /mir-149 polymorphisms and colorectal cancer (CRC). A literature search of PubMed, Web of Science and ScienceDirect was conducted to identify all relevant studies. Three genetic models with pooled ratio and 95% confidence interval were used to evaluate the associations. We found that mir-196a2 polymorphism was significantly associated with CRC in Asian group (additive model: OR = 1.197, 95%CI 1.084 ~ 1.32, P < 0.001; dominant model: OR = 1.247, 95%CI 1.065 ~ 1.46, P = 0.006; recessive model: OR = 1.298, 95%CI 1.101 ~ 1.531, P = 0.002). And no associations were observed between SNPs of mir-146a, mir-149 and CRC in three genetic models. We also found CRC risk was not associated with mir-146a and mir-149 polymorphisms in population subgroup analysis. The current meta-analysis suggests that mir-196a2 polymorphism is associated with CRC, especially in Asian group. While, no associations have been found between mir-146a /mir-149 polymorphisms and CRC.

Assessment of association between genetic variants in microRNA genes hsa-miR-499, hsa-miR-196a2 and hsa-miR-27a and prostate cancer risk in Serbian population

Due to their potentially functional significance, genetic variants within microRNA genes have been recognized as candidates for cancer-related genetic biomarkers. Among the most extensively studied so far are rs3746444, rs11614913 and rs895819. Nevertheless, only few previous studies in Asian population analyzed the association of rs3746444 and rs11614913 with prostate cancer (PCa) risk, while rs895819 was not evaluated in relation to this issue. The aim of this study was to assess the possible association between these genetic variants and PCa risk and progression in Serbian population. 355 samples of peripheral blood were obtained from the patients with PCa and 353 samples from patients with benign prostatic hyperplasia (BPH). 312 volunteers derived from general population who gave samples of buccal swabs were included in the control group. Genotyping of rs3746444, rs11614913 and rs895819 was performed by using PCR-RFLP method, HRM analysis and allele-specific PCR, respectively. Allelic and genotypic associations were evaluated by unconditional linear (for serum PSA level in PCa patients) and logistic regression method with adjustment for age. Minor allele C of rs895819 was found to be associated with the increased risk of developing PCa under dominant (P=0.035; OR=1.38, 95%CI 1.02-1.86) and overdominant (P=0.04; OR=1.37, 95%CI 1.01-1.85) genetic model. Same genetic variant was found to be associated with the clinical stage of localized PCa, as well as with the presence of distant metastases. Allele G of rs3746444 was also shown to be associated with the decreased risk of PCa progression. According to our data, rs3746444 qualifies for a genetic variant potentially associated with PCa aggressiveness in Serbian population. Furthermore, our study provided the first evidence of association between rs895819 and PCa risk, as well as for its genetic association with the presence of distant metastases among PCa patients.

Effects of Two Common Polymorphisms rs2910164 in miR-146a and rs11614913 in miR-196a2 on Gastric Cancer Susceptibility

Background. Single nucleotide polymorphisms (SNPs) in genes encoding microRNAs may play important role in the development of gastric cancer. It has been reported that common SNPs rs2910164 in miR-146a and rs11614913 in miR-196a2 are associated with susceptibility to gastric cancer. The published results remain inconclusive or even controversial. A meta-analysis was conducted to quantitatively assess potential association between the two common SNPs and gastric cancer risk. Methods. A comprehensive literature search was performed in multiple internet-based electronic databases. Data from 12 eligible studies were extracted to estimate pooled odds ratios (ORs) and 95% confidence intervals (95% CI). Results. C allele of rs2910164 is associated with reduced gastric cancer risk in heterozygote model and dominant model whereas rs11614913 indicates no significant association. Subgroup analysis demonstrates that C allele of rs2910164 and rs11614913 may decrease susceptibility to diffuse type gastric cancer in dominant model and recessive model, respectively, while rs11614913 increased intestinal type gastric cancer in dominant model. Conclusion. SNPs rs2910164 and rs11614913 might have effect on gastric cancer risk in certain genetic models and specific types of cancer. Further well-designed studies should be considered to validate the potential effect.

Sequence Variation in Mature MicroRNA-499 Confers Unfavorable Prognosis of Lung Cancer Patients Treated with Platinum-Based Chemotherapy

PURPOSE

This study was implemented to investigate the associations between SNP in mature microRNA (miRNA) sequence and lung cancer prognosis and to verify the function of those SNP.

EXPERIMENTAL DESIGN

Eight SNPs (rs3746444T>C in hsa-mir-499, rs4919510C>G in hsa-mir-608, rs13299349G>A in hsa-mir-3152, rs12220909G>C in hsa-mir-4293, rs2168518G>A in hsa-mir-4513, rs8078913T>C in hsa-mir-4520a, rs11237828T>C in hsa-mir-5579, and rs9295535T>C in hsa-mir-5689) were analyzed in a southern Chinese population with 576 patients with lung cancer, and the significant results were validated in two additional cohorts of 346 and 368 patients, respectively. A series of experiments were performed to evaluate the relevancies of those potentially functional SNPs.

RESULTS

We found that the microRNA-499 rs3746444T>C polymorphism exhibited a consistently poor prognosis for patients with lung cancer in the discovery set [HR, 1.24; 95% confidence interval (CI), 1.02-1.49; P = 0.028], in the validation set I (HR, 1.31; 95% CI, 1.01-1.71; P = 0.048) and in the validation set II (HR, 1.45; 95% CI, 1.12-1.86; P = 0.004). The adverse effect of CT/CC variants was more remarkable in patients receiving platinum-based chemotherapy. Further functional assays demonstrated that the rs3746444C variant allele influences the expression of several cancer-related genes and affects lung cancer cells' proliferation and tumor growth in vivo and in vitro via the cisplatinum resistance.

CONCLUSION

Our findings suggested that the rs3746444T>C polymorphism in mature miR-499 sequence could contribute to poor prognosis by modulating cancer-related genes' expression and thus involve tumorigenesis and anti-chemotherapy, which may be a useful biomarker to predict lung cancer patients' prognosis.

A common polymorphism in pre-miR-146a underlies Hirschsprung disease risk in Han Chinese

BACKGROUND

Hirschsprung disease (HSCR) is a rare multigenic congenital disorder characterized by the absence of the enteric ganglia. To date, single nucleotide polymorphisms (SNPs) in pre-miRNAs have been confirmed related with some diseases. Thus, we hypothesized that pre-miRNA polymorphisms might contribute to HSCR susceptibility. We investigated whether rs2910164 and rs11614913 of pre-miR-146a and pre-miR-196a2, are associated with HSCR.

METHODS

Polymorphisms were genotyped using the Taqman method. Real-time PCR was used for detecting the expression level of miR-146a and its target gene ROBO1 in CC and GG genotypes.

RESULTS

Significant differences were found in the genotype distribution of rs2910164 and rs11614913 polymorphism between HSCR cases and controls (p = 0.023 and 0.041, respectively). Furthermore, G allele of rs2910164 might increase the risk of HSCR (OR, 1.54; 95% CI, 1.06-2.23). Moreover, the expression level of miR-146a for homozygote GG was also higher than homozygote CC (p = 0.0193). In contrast, the expression level of its target gene ROBO1 predicted in bioinformatics for homozygote GG was much lower than homozygote CC (p = 0.0096).

CONCLUSIONS

Our results showed that the polymorphism rs2910164 in pre-miR-146a might alter the production of mature miR-146a and then down-regulate the target gene ROBO1, which plays an important role in pathogenesis of HSCR.

Evaluation of a novel functional single-nucleotide polymorphism (rs35010275 G>C) in MIR196A2 promoter region as a risk factor of gastric cancer in a Chinese population

Single-nucleotide polymorphisms (SNPs) in microRNAs (miRNAs) have been suggested to influence the occurrence and progression of cancer through altering the expression and biological function of miRNAs. The aim of this study was to investigate whether the potential functional SNPs in MIR196A2 promoter had effect on the susceptibility to gastric cancer (GC) in a Chinese population.We conducted a 2-stage case-control study (753 cases and 854 controls in testing set; 940 cases and 1061 controls in validation set) to evaluate the association between 2 potential functional SNPs in MIR196A2 promoter (rs12304647 A>C and rs35010275 G>C) and GC risk. The luciferase reporter assay and electrophoretic mobility shift assay were used to examine the functionality of the important polymorphism.We found that the rs35010275 C allele was significantly associated with the decreased risk of GC (adjusted odds ratio = 0.85, 95% confidence interval = 0.77-0.94) in the combined case-control studies. The miR-196a expression levels in GC tissues were significantly higher than that in corresponding adjacent normal tissues (P < 0.001). Besides, each allele of rs35010275 displayed completely opposite effects to influence the transcription activity of MIR196A2 promoter via recruiting different transcription factors or complexes.The functional rs35010275 G>C polymorphism in MIR196A2 promoter was significantly associated with miR-196a expression and influenced the genetic susceptibility to GC.

Prognostic role of common microRNA polymorphisms in cancers: evidence from a meta-analysis

BACKGROUND

The morbidity and mortality of cancer increase remarkably every year. It's a heavy burden for family and society. The detection of prognostic biomarkers can help to improve the theraputic effect and prolong the lifetime of patients. microRNAs have an influential role in cancer prognosis. The results of articles discussing the relationship between microRNA polymorphisms and cancer prognosis are inconsistent.

METHODS

We conduct a meta-analysis of 19 publications concerning the association of four common polymorphisms, mir-146a rs2910164, mir-149 rs2292832, mir-196a2 rs11614913 and mir-499 rs3746444, with cancer prognosis. Pooled Hazard Ratios with 95% Confidence Intervals for the relationship between four genetic polymorphisms and Overall Survival, Recurrence-free Survival, Disease-free survival, recurrence are calculated. Subgroup analysis by population and type of tumor are conducted.

RESULTS

GG genotype of mir-146a may be the protective factor for overall survival, especially in Caucasian population. C-containing genotypes of mir-196a2 act as a risk role for overall survival. The same result exists in Asian population, in Non-Small Cell Lung Cancer and digestive cancer. The patients with C allele of mir-149 have a better overall survival, especially in Non-Small Cell Lung Cancer. No significant results are obtained for mir-499 polymorphisms.

CONCLUSIONS

Genetic polymorphisms in mir-146a, mir-196a2 and mir-149 may be associated with overall survival. This effect varies with different types of cancer. Genetic polymorphism in mir-499 may have nothing to do with cancer prognosis.

Comprehensive assessment of the association between miRNA polymorphisms and gastric cancer risk

Single nucleotide polymorphisms (SNPs) in pri- or pre-microRNAs (miRNAs) were found to be associated with gastric cancer risk. The aim of this study was to systematically review with update meta-analysis for the association of miRNA SNPs with gastric cancer risk. We systematically reviewed a total of 31 SNPs in the precursor genes of 29 miRNAs associated with overall cancer risk. Meanwhile, 13 case-control studies with a total of 9044 gastric cancer cases and 11,762 controls were included in a meta-analysis of five highly studied pre-miRNA SNPs (miR-146a rs2910164, miR-196a2 rs11614913, miR-499 rs3746444, miR-149 rs2292832 and miR-27a rs895819). Our results show both the homozygous miR-27a rs895819 and the miR-149 rs2292832 heterozygote genotype were associated with a decreased risk of gastric cancer when compared with wild type. In the stratified analysis, in some subgroup, heterozygous miR-146a rs2910164 was associated with a decreased risk of gastric cancer; and the variant genotype of miR-196a-2 rs11614913 was associated with an increased risk. No association was found between miR-499 rs3746444 and gastric cancer risk. In summary, miR-27a rs895819 and miR-149 rs2292832 are of potential forewarning ability for gastric cancer risk.

miRNA polymorphisms and risk of gastric cancer in Asian population

miRNAs are endogenous 19- to 25-nt noncoding RNAs that can negatively regulate gene expression by directly cleaving target mRNA or by inhibiting its translation. Recent studies have revealed that miRNA plays a significant role in gastric cancer development either as a tumor suppressor gene or oncogene. miRNA-single-nucleotide polymorphisms (SNPs), as a novel class of functional SNPs/polymorphisms, have been identified as candidate biomarkers for gastric cancer susceptibility. On the basis of recent data, the present review summarizes current knowledge of the functional effects of miRNA-SNPs and their importance as candidate gastric cancer biomarkers. Additionally, this review also includes a meta-analysis of the most frequently studied miRNA-SNPs in gastric cancer.

Association between miR-146aG>C and miR-196a2C>T polymorphisms and the risk of hepatocellular carcinoma in a Chinese population

MicroRNAs have been demonstrated to have a role in susceptibility and prognosis of various types of human cancer. We investigated the association between polymorphisms in miR-146aG>C, miR-196a2C>T, and miR-499A>G and hepatocellular carcinoma (HCC) risk and interaction with HCC and hepatitis B virus (HBV) infection. Two hundred sixty-six cases with HCC and 281 health controls were enrolled in the present study. Genotyping of the miR-146aG>C, miR-196a2C>T, and miR-499A>G genotypes was conducted by duplex polymerase chain reaction with the confronting two-pair primer (PCR-RFLP). Subjects with miR-146a GG and G allele had an increased risk of HCC compared with the homozygote CC genotype. Similarly, HCC patients carrying microRNA (miRNA)-196a2 computed tomography, TT, and T allele significantly decreased the risk of HCC relative to the CC genotype. Stratified analysis indicated that miR-196a2C>T polymorphism was associated with reduced risk of HBV-related HCC, but not in hepatitis C virus- and nonviral-related HCC cases. In conclusion, miR-146aG>C and miR-196a2C>T polymorphism are associated with risk of HCC patients in China, especially in patients with HBV infection. SNPs in miRNA sequences can be used as a diagnostic biomarker for HCC.

Genetic variations in microRNAs and the risk and survival of renal cell cancer

MicroRNAs (miRNAs) are a class of short non-coding, single-stranded RNAs, which perform posttranscriptional regulatory functions as tumor suppressors or oncogenes. Single nucleotide polymorphisms (SNPs) in microRNAs (miRNAs) genes are currently being identified for contributing to cancer risk, prognosis and survival. We investigated whether genetic variations of miRNAs were associated with the risk and prognosis of renal cell carcinoma (RCC). We genotyped four common miRNA SNPs (i.e. miR-146a rs2910164, miR-149 rs2292832, miR-196a2 rs11614913 and miR-499 rs3746444) to assess their associations with RCC risk in a two-stage case-control study (355 cases and 362 controls in discovery set, meanwhile 647 cases and 660 controls in validation set), as well as RCC survival in 311 patients. We found that the miR-196a2 SNP rs11614913 was associated with RCC susceptibility in recessive model [CC versus TT/TC, adjusted odds ratio = 0.65, 95% confidence interval (CI) = 0.52-0.83] and with survival of RCC in dominant model (TC/CC versus TT, adjusted hazard ratio = 0.40, 95% CI = 0.18-0.89). Meanwhile, the rs11614913 CC genotype was associated with the significantly decreased expression of miR-196a-5p in 26 renal cancer tissues (P = 0.018). Moreover, luciferase reporter assays revealed the potential effect of rs11614913 SNP on the binding of miR-196a-3p to its targets. These results suggested that the miR-196a2 rs11614913 may contribute to the genetic susceptibility and prognosis for RCC, which may act as a biomarker for RCC occurrence and prognosis.

Gene polymorphisms of micrornas in Helicobacter pylori-induced high risk atrophic gastritis and gastric cancer

BACKGROUND AND AIMS

MicroRNAs (miRNAs) are known for their function as translational regulators of tumor suppressor or oncogenes. Single nucleotide polymorphisms (SNPs) in miRNAs related genes have been shown to affect the regulatory capacity of miRNAs and were linked with gastric cancer (GC) and premalignant gastric conditions. The purpose of this study was to evaluate potential associations between miRNA-related gene polymorphisms (miR-27a, miR-146a, miR-196a-2, miR-492 and miR-608) and the presence of GC or high risk atrophic gastritis (HRAG) in European population.

METHODS

Gene polymorphisms were analyzed in 995 subjects (controls: n = 351; GC: n = 363; HRAG: n = 281) of European descent. MiR-27a T>C (rs895819), miR-146a G>C (rs2910164), miR-196a-2 C>T (rs11614913), miR-492 G>C (rs2289030) and miR-608 C>G (rs4919510) SNPs were genotyped by RT-PCR.

RESULTS

Overall, SNPs of miRNAs were not associated with the presence of GC or HRAG. We observed a tendency for miR-196a-2 CT genotype to be associated with higher risk of GC when compared to CC genotype, however, the difference did not reach the adjusted P-value (odds ratio (OR) - 1.46, 95% confidence interval (CI) 1.03-2.07, P = 0.032). MiR-608 GG genotype was more frequent in GC when compared to controls (OR -2.34, 95% CI 1.08-5.04), but significance remained marginal (P = 0.029). A similar tendency was observed in a recessive model for miR-608, where CC + CG vs GG genotype comparison showed a tendency for increased risk of GC with OR of 2.44 (95% CI 1.14-5.22, P = 0.021). The genotypes and alleles of miR-27a, miR-146a, miR-196a-2, miR-492 and miR-608 SNPs had similar distribution between histological subtypes of GC and were not linked with the presence of diffuse or intestinal-type GC.

CONCLUSIONS

Gene polymorphisms of miR-27a, miR-146a, miR-196a-2, miR-492, miR-492a and miR-608 were not associated with the presence of HRAG, GC or different histological subtypes of GC in European subjects.

A functional polymorphism in MIR196A2 is associated with risk and progression of nasopharyngeal carcinoma in the Chinese population

BACKGROUND

Genetic variations in microRNAs may alter their processing, expression, and binding to target mRNAs, consequently affecting many cancer-related biological processes. Recently, a polymorphism rs11614913 in MIR196A2 was shown to affect the processing of the precursor microRNA into its mature forms and the repertoire of target mRNAs with which it interacts. We examined whether this polymorphism was relevant to the risk of occurrence or progression of nasopharyngeal carcinoma (NPC) in the Chinese population.

METHODS

We genotyped the MIR196A2 rs11614913 in a case-control study of 1084 patients with NPC and 1036 cancer-free controls using the TaqMan assay. The genetic associations with the risk of occurrence and progression of NPC were analyzed by logistic regression.

RESULTS

We observed a significantly increased occurrence of NPC associated with the rs11614913 T allele (odds ratio [OR]=1.15, 95% confidence interval [CI]=1.02-1.32, p=0.026) compared with the C allele. The T allele was also significantly associated with the advanced local tumor invasion (T₃+T₄ vs. T₁+T₂; OR=1.27, 95% CI=1.04-1.54, p=0.015) and advanced lymph node metastasis (N₂+N₃ vs. N₀+N₁; OR=1.23, 95% CI=1.02-1.49, p=0.031) of NPC compared with the C allele. Furthermore, stratified analysis indicated that the increased susceptibility to advanced lymph node metastasis of NPC related to the T allele was more pronounced in patients with a positive family history (N₂+N₃ vs. N₀+N₁; p=0.016, test for homogeneity).

CONCLUSIONS

Our study suggests that the functional polymorphism rs11614913 in the MIR196A2 gene may contribute to the risk of occurrence and progression of NPC in the Chinese population.

Gastric cancer: epidemiologic aspects

A multifactorial and multistep model of gastric cancer (GC) is currently accepted, according to which different environmental and genetic factors are involved at different stages in the cancer process. The aim of this article is to review the most relevant information published on the relative contribution of genetic and environmental factors. Large meta-analyses confirmed the association between IL8, IL10, TNF-b, TP53 and PSCA, while genetic variation at different genes such as XPG, PLCE1, HFE, ERCC5, EZH2, DOC2, CYP19A1, ALDH2, and CDH1 have been reported to be associated with GC risk. Several microRNAs have also been associated with GC and their prognosis. Cohort studies have shown the association between GC and fruit, flavonoid, total antioxidant capacity, and green tea intake. Obesity was associated with cardia GC, heme iron intake from meat with GC risk. Several large meta-analyses have confirmed the positive association of GC with salt intake and pickled foods and the negative association with aspirin use.