Common genetic variants in pre-microRNAs and risk of breast cancer in the North Indian population

Functional gene polymorphisms and expression alteration of selected microRNAs and the risk of various gastric lesions in Helicobacter pylori-related gastric diseases

Background: Helicobacter pylori (Hp) persistent infection is an important pathogenic factor for a series of chronic gastric diseases from chronic gastritis to gastric cancer. Genetic and epigenetic abnormalities of microRNAs may play a vital role in the pathological evolution of gastric mucosa in Helicobacter pylori-related gastric diseases (HPGD). This study aimed to investigate the relationship between miR-146a, miR-196a2, miR-149, miR-499 and miR-27a gene single nucleotide polymorphisms (SNPs) and their expressions with pathological changes in gastric mucosa, and to further analyze the interactions between SNPs and Hp. Methods: Subjects in this study included patients diagnosed with HPGD and healthy controls. MiR-146a rs2910164, miR-196a2 rs11614913, miR-149 rs2292832, miR-499 rs3746444 and miR-27a rs895819 were genotyped by direct sequencing. Fluorescence quantitative PCR was used to detect microRNA expressions. Gene-gene and gene-environment interactions were evaluated by multifactor dimensionality reduction (MDR) method. Results: we found that frequency distribution of miR-196a2 rs11614913 CT genotype in gastric precancerous lesion (GPL) group and gastric cancer (GC) group was significantly higher than normal control (NOR) group [adjusted OR = 6.16, 95%CI (1.46-26.03); adjusted OR = 11.83, 95%CI (1.65-84.72), respectively]. CT genotype and C allele of miR-27a rs895819 were associated with increased risk of GC [adjusted OR = 10.14, 95%CI (2.25-45.77); adjusted OR = 3.71, 95%CI(1.46-9.44), respectively]. The MDR analysis results showed that the interaction between miR-196a2 rs11614913 and Hp was associated with the risk of GPL (p = 0.004). Meanwhile, the expression level of miR-196a2 in GC group was significantly higher than NOR, chronic inflammation (CI) and early precancerous lesion (EPL) groups among Hp-positive subjects. And expressions of miR-499 and miR-27a in GC group were both higher than EPL group. Also, miR-27a expression in GC group was higher than CI and gastric atrophy (GA) groups. Conclusion: miR-196a2 rs11614913 and miR-27a rs895819 may affect the genetic susceptibility to GPL or GC. MiR-196a2 rs11614913 and Hp have a synergistic effect in the occurrence and development of GPL. The up-regulation of miR-499, miR-196a2 and miR-27a expression caused by Hp infection may be an important mechanism of gastric carcinogenesis.

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.

Association between single-nucleotide polymorphisms in miRNA and breast cancer risk: an updated review

Breast cancer (BC), a heterogeneous, aggressive illness with high mortality, is essentially a genomic disease. While the high-penetrance genes BRCA1 and BRCA2 play important roles in tumorigenesis, moderate- and low-penetrance genes are also involved. Single-nucleotide polymorphisms (SNPs) in microRNA (miRNA) genes have recently been identified as BC risk factors. miRNA genes are currently classified as low-penetrance. SNPs are the most common variations in the human genome. While the role of miRNA SNPs in BC susceptibility has been studied extensively, results have been inconsistent. This review analyzes the results of association studies between miRNA SNPs and BC risk from countries around the world. We conclude that: (a) By continent, the largest proportion of studies to date were conducted in Asia (65.0 %) and the smallest proportion in Africa (1.8 %); (b) Association studies have been completed for 67 different SNPs; (c) 146a, 196a2, 499, 27a, and 423 are the most-studied miRNAs; (d) The SNPs rs2910164 (miRNA-146a), rs11614913 (miRNA-196a2), rs3746444 (miRNA-499) and rs6505162 (miRNA-423) were the most widely associated with increased BC risk; (e) The majority of studies had small samples, which may affect the precision and power of the results; and (f) The effect of an SNP on BC risk depends on the ethnicity of the population. This review also discusses potential explanations for controversial findings.

Characteristics of miRNA-SNPs in healthy Japanese subjects and non-small cell lung cancer, colorectal cancer, and soft tissue sarcoma patients

Single nucleotide polymorphisms in genes encoding microRNAs (miRNA-SNPs) may affect the maturation steps of miRNAs or target mRNA recognition, leading to changes in the expression of target mRNAs to cause gain- or loss-of-function changes. Several miRNA-SNPs are known to be associated with the risk of diseases such as cancer. The purpose of this study was to comprehensively determine the miRNA-SNPs in Japanese individuals to evaluate the differences in allele frequencies between ethnicities by comparing data from the global population in the 1000 Genomes Project and differences between healthy subjects and cancer patients. We performed next-generation sequencing targeting genes encoding 1809 pre-miRNAs. As a result, 403 miRNA-SNPs (146 miRNA-SNPs per subject on average) were identified in 28 healthy Japanese subjects. We observed significant differences in the allele frequencies between ethnicities in 33 of the 403 miRNA-SNPs. The numbers of miRNA-SNPs per subject in 44 non-small cell lung cancer (NSCLC), 33 colorectal cancer (CRC), and 15 soft tissue sarcoma (STS) patients were almost equal to those in healthy subjects. Significant differences in allele frequencies were observed for 14, 11, and 9 miRNA-SNPs in NSCLC, CRC, and STS patients compared with the frequencies in healthy subjects, suggesting that these SNPs can be biomarkers of risk for each type of cancer assessed. In summary, we comprehensively characterized miRNA-SNPs in Japanese individuals and found differences in allele frequencies of several miRNA-SNPs between ethnicities and between healthy subjects and cancer patients. Studies investigating a larger number of subjects should be performed to confirm the potential of miRNA-SNPs as biomarkers of cancer risk.

Single nucleotide polymorphisms in microRNAs action as biomarkers for breast cancer

MicroRNAs (miRNAs) have been recently described as small noncoding RNAs that are involved in numerous crucial physiological processes, such as cell cycles, differentiation, development, and metabolism. Thus, dysregulation of these molecules could lead to several severe disorders, including breast cancer (BC). Ongoing investigations in malignant growth diagnostics have distinguished miRNAs as promising disease biomarkers. As with any other mRNAs, single nucleotide polymorphisms (SNPs) in DNA sequence encoding for miRNA (miR-SNPs) indeed lead to potential changes in the function of miRNA. In this study, miR-SNPs located in different miRNA sequence regions, which have been associated with BC in different ways, and the potential mechanisms of how these miR-SNPs develop the risk of the disease were discussed.

Association between MIR499A rs3746444 polymorphism and breast cancer susceptibility: a meta-analysis

Numerous studies have investigated the association of MIR499A rs3746444 polymorphism with breast cancer susceptibility, but the results have been inconsistent. In this work, we performed a meta-analysis to obtain a more reliable estimate of the association between the polymorphism and susceptibility to breast cancer. A comprehensive literature search was conducted on PubMed, Scopus, Web of Science (WoS), China National Knowledge Infrastructure (CNKI), VIP and Wanfang databases up to January 2020. A total of 14 studies involving 6,797 cases and 8,534 controls were included for analysis under five genetic models: homozygous (GG vs. AA), heterozygous (AG vs. AA), dominant (AG + GG vs. AA), recessive (GG vs. AA + AG) and allele (G vs. A). A statistically significant association was observed between the polymorphism and an increased breast cancer susceptibility under all genetic models (homozygous, OR = 1.33, 95% CI = 1.03-1.71, P = 0.03; heterozygous, OR = 1.08, 95% CI = 1.00-1.16, P = 0.04; dominant, OR = 1.15, 95% CI = 1.02-1.30; P = 0.03; recessive, OR = 1.35, 95% CI = 1.06-1.72, P = 0.01; allele, OR = 1.12, 95% CI = 1.00-1.26, P = 0.04). Subgroup analysis based on ethnicity suggested that significant association was present only among Asians, but not Caucasians. In conclusion, MIR499A rs3746444 polymorphism was significantly associated with breast cancer susceptibility among Asians, suggesting its potential use as a genetic risk marker in this population.

Evidences from a Systematic Review and Meta-Analysis Unveil the Role of MiRNA Polymorphisms in the Predisposition to Female Neoplasms

Breast (BCa) and gynecological (GCa) cancers constitute a group of female neoplasms that has a worldwide significant contribution to cancer morbidity and mortality. Evidence suggests that polymorphisms influencing miRNA function can provide useful information towards predicting the risk of female neoplasms. Inconsistent findings in the literature should be detected and resolved to facilitate the genetic screening of miRNA polymorphisms, even during childhood or adolescence, and their use as predictors of future malignancies. This study represents a comprehensive systematic review and meta-analysis of the association between miRNA polymorphisms and the risk of female neoplasms. Meta-analysis was performed by pooling odds-ratios (ORs) and generalized ORs while using a random-effects model for 15 miRNA polymorphisms. The results suggest that miR-146a rs2910164 is implicated in the susceptibility to GCa. Moreover, miR-196a2 rs11614913-T had a moderate protective effect against female neoplasms, especially GCa, in Asians but not in Caucasians. MiR-27a rs895819-G might pose a protective effect against BCa among Caucasians. MiR-499 rs3746444-C may slightly increase the risk of female neoplasms, especially BCa. MiR-124 rs531564-G may be associated with a lower risk of female neoplasms. The current evidences do not support the association of the remaining polymorphisms and the risk of female neoplasms.

Polymorphisms in miRNAs Gene (146a, 149, 196a) and Susceptibility to ARV-associated Hepatotoxicity

Background:

Micro RNAs act as a regulatory layer for pharmacogenomics-related gene ex-pression. It could play a role in the efficacy and toxicity of the drug. The SNPs in miRNA genes are linked with different functional consequences.

Methods:

Hence, we examined the miR (146a G/C, 149C/T, and 196aC/T) polymorphisms in 34 pa-tients with hepatotoxicity, 123 patients without hepatotoxicity, and 155 healthy controls using a PCR-RFLP method.

Results:

In patients with hepatotoxicity, miR196aCT genotype and combined genotype GCT showed a risk for hepatotoxicity severity with borderline significance (OR=2.08, P=0.07; OR=2.88, P=0.06). While comparing between patients with hepatotoxicity and healthy controls, the combined genotypes CCC and GCT have shown a susceptibility to hepatotoxicity severity (OR=2.89, P=0.05; OR=2.60, P=0.09). The miR196TT genotype was associated with the individuals of advanced HIV disease stage (OR=3.68, P=0.04). In HIV patients who consumed alcohol and did not have hepatotoxicity, the miR 196aCT genotype showed susceptibility to acquisition of hepatotoxicity with borderline significance (OR=2.36, P=0.06).

Discussion:

The miR149TT and 196aTT genotypes showed a risk of acquisition of hepatotoxicity to nevirapine usage among HIV patients without hepatotoxicity (OR=4.19, P=0.07; OR=1.97, P=0.84). In HIV patients with and without hepatotoxicity, the miR 196aCT genotype showed a risk of acquisition of hepatotoxicity and its severity to the combined use of alcohol and nevirapine, respectively (OR=14.18, P=0.08; OR=2.29, P=0.08). In multivariate logistic regression, taking nevirapine, 196aCT genotype had an independent risk factor for hepatotoxicity severity (OR=5.98, P=0.005; OR=2.38, P=0.05).

Conclusion: In conclusion, miR196aC/T polymorphism and combined genotypes GCT and CCC may facilitate the risk for acquisition of hepatotoxicity and its severity

Association of miR-146a, miR-149 and miR-196a2 polymorphisms with neuroblastoma risk in Eastern Chinese population: a three-center case-control study

Neuroblastoma is one of the most common malignancy in childhood, which originates from the developing sympathetic nervous system. Single nucleotide polymorphisms (SNPs) in primary miRNA (pri-miRNA) have shown to associate with cancer susceptibility, including neuroblastoma. Three precursor miRNA (pre-miRNA) SNPs (pre-miR-146a rs2910164, pre-miR-149 rs2292832 and pre-miR-196a2 rs11614913) were found to contribute to pathogenesis of various diseases. Here, to evaluate the association among these three pre-miRNA SNPs and neuroblastoma susceptibility in Eastern Chinese children, we carried out a three-center case-control study involving 312 neuroblastoma cases and 762 healthy controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the association of these three polymorphisms with neuroblastoma risk. However, no significant association was observed among these three SNPs and neuroblastoma susceptibility, in either overall or subgroups analysis by tumor sites, gender and age. Further larger studies consisting of diverse ethnic populations are required to clarify the associations among these three pre-miRNAs polymorphisms and neuroblastoma risk.

Impacts of single nucleotide polymorphisms in three microRNAs (miR-146a, miR-196a2 and miR-499) on the susceptibility to cervical cancer among Indian women

Background: Cervical cancer is the second major female cancer in India and constitutes one-fourth of the world’s burden. Human Papilloma Virus (HPV) infection is an essential but insufficient cause for cervical cancer. Genetic variants in microRNAs (miRNAs/miRs) play an important role in the susceptibility of various types of cancers.

Objective: To evaluate the association of Single Nucleotide Polymorphisms (SNPs) in miR-146a (rs2910164), miR-196a2 (rs11614913), and miR-499 (rs3746444), with cervical cancer susceptibility in Indian population.

Methods: Three hundred samples were genotyped by Polymerase chain reaction (PCR)-Restriction fragment length polymorphism (RFLP). Both patients and controls were also screened for the presence of HPV DNA.

Results: In this case–control study, 125 (83.3%) cervical cancer cases were found to be infected with HPV DNA. The frequency of miR-146a C allele was higher in controls than in cases [odds ratio (OR) (95% confidence interval (CI)) = 0.81 (0.57–1.14), P-value = 0.258]. miR-196a2 T allele was found to be associated with the decreased risk of cervical cancer [OR (95% CI) = 0.36 (0.26–0.50), P-value<0.0001]. Approximately 1.22-fold increased risk has been observed in individuals carrying miR-499 TT genotypes [OR (95% CI) = 1.22 (0.63–2.36), P-value = 0.617]. Interaction studies for miR-196a2/miR-499 loci showed that women carrying TT/CC and TT/CT genotypes were less likely to develop cervical cancer than CC/CC combination [P<0.05]. Likewise, miR-146a/miR-196a2 genotypic combinations (CC/TT, CG/TT, GG/TT) followed the similar trend [P<0.05], exhibited the protective effect against cervical cancer with reference to CC/CC group. Combined genotypes of miR-146a/miR-499 [CC/CT, CG/CC, CG/CT, CG/TT, GG/CC, GG/CT, GG/TT] demonstrated a non-significant trend toward higher cervical cancer risk [OR > 1.00, P>0.05].

Conclusion: Polymorphisms in miR-146a, miR-196a2, and miR-499 individually or collectively have the prospective to emerge as biomarkers for cervical 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.

Genetic Variants in pre-miR-146a, pre-miR-499, pre-miR-125a, pre-miR-605, and pri-miR-182 Are Associated with Breast Cancer Susceptibility in a South American Population

Breast cancer (BC) is one of the most frequent tumors affecting women worldwide. microRNAs (miRNAs) single-nucleotide polymorphisms (SNPs) likely contribute to BC susceptibility. We evaluated the association of five SNPs with BC risk in non-carriers of the BRCA1/2-mutation from a South American population. The SNPs were genotyped in 440 Chilean BRCA1/2-negative BC cases and 1048 controls. Our data do not support an association between rs2910164:G>C or rs3746444:A>G and BC risk. The rs12975333:G>T is monomorphic in the Chilean population. The pre-miR-605 rs2043556-C allele was associated with a decreased risk of BC, both in patients with a strong family history of BC and in early-onset non-familial BC (Odds ratio (OR) = 0.5 [95% confidence interval (CI) 0.4⁻0.9] p = 0.006 and OR = 0.6 [95% CI 0.5⁻0.9] p = 0.02, respectively). The rs4541843-T allele is associated with increased risk of familial BC. This is the first association study on rs4541843 and BC risk. Previously, we showed that the TOX3-rs3803662:C>T was significantly associated with increased risk of familial BC. Given that TOX3 mRNA is a target of miR-182, and that both the TOX3 rs3803662-T and pri-miR-182 rs4541843-T alleles are associated with increased BC risk, we evaluated their combined effect. Risk of familial BC increased in a dose-dependent manner with the number of risk alleles (p-trend = 0.0005), indicating an additive effect.

A Meta-Analysis of miR-499 rs3746444 Polymorphism for Cancer Risk of Different Systems: Evidence From 65 Case-Control Studies

MicroRNAs (miRNAs) are a class of endogenous, short and non-coding RNAs that may play important roles in the pathogenesis of tumor. The associations between microRNA-499 rs3746444 polymorphism and cancer risk in different systems remain inconclusive. This article is aimed to obtain more exact estimation of these relationships through a meta-analysis based on 52,456 individuals. We retrieved relevant and eligible studies from Pubmed and Embase database up to January 10, 2018. ORs and 95% CIs were used to estimate the associations between miR-499 polymorphism and cancer susceptibility in different systems. All analyses were performed using the Stata 11.0 software. A total of 65 case-control studies were retrieved using explicit inclusion and exclusion criteria. The study included 23,762 cases and 28,694 controls. Overall cancer analysis showed the association between miR-499 polymorphism and susceptibility to cancer was significant. MicroRNA-499 rs3746444 was found to be significantly associated with increased risk of cancer of the respiratory system (CC vs. TT: OR = 1.575, 95% CI = 1.268–1.955, CC vs. TC+TT: OR = 1.527, 95% CI = 1.232–1.892), digestive system (CC vs. TT: OR = 1.153, 95% CI = 1.027–1.295; TC vs. TT: OR = 1.109, 95% CI = 1.046–1.176; CC+TC vs. TT: OR = 1.112, 95% CI = 1.018–1.216; CC vs. TC+TT: OR = 1.137, 95% CI = 1.016–1.272; C vs. T: OR = 1.112, 95% CI = 1.025–1.206), urinary system (TC vs. TT: OR = 1.307, 95% CI = 1.130–1.512; CC+TC vs. TT: OR = 1.259, 95% CI = 1.097–1.446; C vs. T: OR = 1.132, 95% CI = 1.014–1.264), and gynecological system (C vs. T: OR = 1.169, 95% CI = 1.002–1.364). In the subgroup analysis by ethnicity, the result showed that significant association with an increased cancer risk was found in Asian. Subgroup analysis based on type of tumor was also performed, miR-499 rs3746444 is associated with susceptibility of cervical squamous cell carcinoma, lung cancer, prostate cancer, and hepatocellular carcinoma.

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.

Association between three functional microRNA polymorphisms (miR-499 rs3746444, miR-196a rs11614913 and miR-146a rs2910164) and breast cancer risk: a meta-analysis

Three functional microRNA polymorphisms (miR-499 rs3746444 A > G, miR-196a rs11614913 C > T and miR-146a rs2910164 G > C) have been reported to be associated with breast cancer (BC) risk. However, the results of the published studies are inconsistent. In order to obtain a more credible result, we conducted this meta-analysis. We searched PubMed, EMBASE and Web of Science databases to identify relevant studies. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the association. Thirty-eight eligible studies with 17,417 cases and 18,988 controls were included in this meta-analysis. Our results showed that the rs3746444 was associated with an increased breast cancer risk in the four genetic models (G vs. A: OR = 1.17, P = 0.008; GG vs. AA: OR = 1.41, P < 0.001; AG vs. AA: OR = 1.10, P = 0.036; GG+AG vs. AA: OR = 1.16, P = 0.001). In the subgroup analysis by ethnicity, significant correlation remained in Asians but not in Caucasians. For rs11614913, obvious decreased breast cancer risk was observed in Caucasian populations (T vs. C: OR = 0.93, P = 0.044). However, we couldn't detect an association between rs2910164 and breast cancer risk. This meta-analysis demonstrates that rs3746444 could increase breast cancer risk in Asians and in general populations, while rs11614913 could decrease the risk of breast cancer in Caucasians. The rs2910164 polymorphism has no association with breast cancer risk. More multicenter studies with larger sample sizes are required to verify our results.

Association of miR-196a2 rs11614913 and miR-499 rs3746444 polymorphisms with cancer risk: a meta-analysis

Background

MicroRNAs (miRNAs) are small non-coding RNA molecules, which participate in diverse biological processes and may regulate tumor suppressor genes or oncogenes. Rs11614913 in miR-196a2 and rs3746444 in miR-499 are shown to associate with increased/decreased cancer risk. This meta-analysis was performed to systematically assess the overall association.

Materials and Methods

We searched Pubmed, Web of Knowledge, EMBASE, Chinese National Knowledge Infrastructure (CNKI) databases until December 2016 to identify eligible studies. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to estimate the strength of the associations.

Results

We assessed published studies of the association between these microRNA polymorphisms and cancer risk from 56 studies with 21958/26436 cases/controls for miR-196a2 and from 37 studies with 13759/17946 cases/controls for miR-499. The results demonstrated that miR-196a2 rs11614913 was significantly associated with a decreased cancer risk, in particular with a decreased risk for colorectal cancer and gastric cancer, or for Asian population subgroup. In addition, miR-499 rs3746444 polymorphism was observed as a risk factor for cancers, in particular, for breast cancer, or for in the Asian population.

Conclusions

Our meta-analysis suggests that the rs11614913 most likely contributes to decreased susceptibility to cancer, especially in Asians and colorectal cancer and gastric cancer, and that the rs3746444 may increase risk for cancer. Furthermore, more well-designed studies with large sample size are still necessary to further elucidate the association between polymorphisms and different kinds of cancers risk.

Investigating the association of rs2910164 with cancer predisposition in an Irish cohort

INTRODUCTION

MicroRNAs (miRNAs) are small noncoding RNA molecules that exert post-transcriptional effects on gene expression by binding with cis-regulatory regions in target messenger RNA (mRNA). Polymorphisms in genes encoding miRNAs or in miRNA-mRNA binding sites confer deleterious epigenetic effects on cancer risk. miR-146a has a role in inflammation and may have a role as a tumour suppressor. The polymorphism rs2910164 in the MIR146A gene encoding pre-miR-146a has been implicated in several inflammatory pathologies, including cancers of the breast and thyroid, although evidence for the associations has been conflicting in different populations. We aimed to further investigate the association of this variant with these two cancers in an Irish cohort.

METHODS

The study group comprised patients with breast cancer (BC), patients with differentiated thyroid cancer (DTC) and unaffected controls. Germline DNA was extracted from blood or from saliva collected using the DNA Genotek Oragene 575 collection kit, using crystallisation precipitation, and genotyped using TaqMan-based PCR. Data were analysed using SPSS, v22.

RESULTS

The total study group included 1516 participants. This comprised 1386 Irish participants; 724 unaffected individuals (controls), 523 patients with breast cancer (BC), 136 patients with differentiated thyroid cancer (DTC) and three patients with dual primary breast and thyroid cancer. An additional cohort of 130 patients with DTC from the South of France was also genotyped for the variant. The variant was detected with a minor allele frequency (MAF) of 0.19 in controls, 0.22 in BC and 0.27 and 0.26 in DTC cases from Ireland and France, respectively. The variant was not significantly associated with BC (per allele odds ratio = 1.20 (0.98-1.46), P  = 0.07), but was associated with DTC in Irish patients (per allele OR = 1.59 (1.18-2.14), P = 0.002).

CONCLUSION

The rs2910164 variant in MIR146A is significantly associated with DTC, but is not significantly associated with BC in this cohort.

Meta-analysis of the association between three microRNA polymorphisms and breast cancer susceptibility

Single nucleotide polymorphisms (SNPs) in three microRNAs (miRNAs), rs2910164 in miR-146a, rs11614913 in miR-196a2, and rs3746444 in miR-499, have been associated with breast cancer (BC) susceptibility, but the evidence is conflicting. To obtain a more robust assessment of the association between these miRNA variants and BC risk, we carried out a meta-analysis through systematic literature retrieval from the PubMed and Embase databases. A total of 9 case-control studies on rs2910164, 12 on rs11614913, and 7 on rs3746444 were included. Pooled odds ratios and 95% confidence intervals were used to evaluate associations with BC risk. Overall analysis showed that rs2910164 was not associated with BC susceptibility in any genetic model, whereas rs11614913 was associated with a decreased risk in both the allelic contrast and recessive models, and rs3746444 imparted an increased risk in all genetic models. Stratified analyses showed that rs11614913 may decrease the risk of BC in the heterozygote model in Asians, and in all genetic models, except the heterozygote model, when the sample size is ≥ 500. Subgroup analysis indicated that rs3746444 was associated with increased risk of BC in Asians, but not Caucasians, at all sample sizes. This meta-analysis suggests that rs11614913 in miR-196a2 may decrease the risk of BC, while rs3746444 in miR-499 may increase it, especially in Asians when the sample size is large. We propose that rs11614913(C > T) and rs3746444 (A > G) may be useful biomarkers predictive of BC risk.

Pre-microRNA Gene Polymorphisms and Risk of Cervical Squamous Cell Carcinoma

Introduction

MicroRNAs (miRNAs) are short (~22 nucleotides) regulatory RNAs that can modulate gene expression and are aberrantly expressed in many diseases, including cancer. It has been suggested that, the presence of single nucleotide polymorphisms in precursor miRNAs (pre-miRNAs) can alter miRNA processing, expression and binding to target mRNA and represents another type of genetic variability, that can contribute to the susceptibility of human cancers.

Aim

The present study investigated the genetic variants in pre-miRNAs (hsa-miRNA-196a2 rs11614913 C/T, hsa-miRNA-499 rs3746444 T/C and hsa-miRNA-146a rs2910164 G/C) for their role in cervical cancer susceptibility.

Materials and Methods

The study comprised 164 controls and 184 patients of cervical cancer. The genotypic frequency of miRNA polymorphisms were determined by using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Logistic regression was used for statistical analysis using SPSS Software version 15.0.

Results

Hsa-miRNA-499 rs3746444 T/C polymorphism showed a statistically significant association with considerable risk for cervical cancer at genotypes (CC, p=0.001, OR=4.801) and variant allele (p<0.001, OR=2.307). MiRNA 146a and miRNA 196a2 polymorphisms showed no association with cervical cancer. However, interaction of miRNA polymorphisms with smoking habit showed higher risk of cervical cancer with miRNA 196a2 polymorphism in patients with smoking but no significant modification in the risk of cervical cancer was seen for other polymorphisms.

Conclusion

The results of the present study demonstrate that, miRNA 499 T/C polymorphism is significantly associated with genetic susceptibility to cervical cancer and may have a role in its pathogenesis.

MicroRNA Polymorphisms in Cancer: A Literature Analysis

Single nucleotide polymorphisms (SNPs) located in microRNA (miRNA) genes (miR-SNPs) have attracted increasing attention in recent years due to their involvement in the development of various types of cancer. Therefore, a systematic review on this topic was needed. From 55 scientific publications we collected 20 SNPs, which are located within 18 miRNA encoding genes and have been associated with 16 types of cancer. Among 20 miRNA gene polymorphisms 13 are located within the premature miRNA region, five within mature, and two within mature seed miRNA region. We graphically visualized a network of miRNA-cancer associations which revealed miRNA genes and cancer types with the highest number of connections. Our study showed that, despite a large number of variations currently known to be located within miRNA genes in humans, most of them have not yet been tested for association with cancer. MicroRNA SNPs collected in this study represent only 0.43% of known miRNA gene variations (20/4687). Results of the present study will be useful to researchers investigating the clinical use of miRNAs, such as the roles of miRNAs as diagnostic markers and therapeutic targets.

Association of four common SNPs in microRNA polymorphisms with the risk of hepatocellular carcinoma

We conducted a case-control study to investigate genetic variants of miR-146a rs2910164, miR-196a2 rs11614913, miR-149 rs2292832 and miR-499 rs3746444 in the development of HCC in a Chinese population. This case-control study included 266 HCC patients and 266 control subjects between January 2012 and December 2013. Conditional logistical regression analysis indicated that TT genotype and T allele of miR-196a2 rs11614913 carried a 2.29-fold (95% CI = 1.30-4.05) and 1.60-fold (95% CI = 1.11-2.32) increased risk of HCC when compared with CC genotype, respectively. The subgroup analysis indicated that the effect of miR-196a2 rs11614913 polymorphism was influence by HBV infection. HBV infection subjects carrying the CT + TT genotype of miR-196a2 rs11614913 had an increased risk of HCC, and the OR (95% CI) was 2.89 (1.19-7.02). In conclusion, miR-196a2 rs11614913 polymorphism may contribute to identifying individuals, especially in HBV-infected subjects, who are at high risk for HCC.