Comprehensive review of genetic association studies and meta-analyses on miRNA polymorphisms and cancer risk

Increased Risk of Thai Childhood Acute Lymphoblastic Leukemia with the MiR196a2 T>C Polymorphism

Objectives:

This study assessed associations of the miR196a2 (rs11614913) T>C polymorphism withsusceptibility to childhood acute lymphoblastic leukemia (ALL) and clinical outcomes.

Materials and Methods:

Blood DNA samples from 104 childhood ALL patients and 180 healthy children were studied for the miR-196a2 (rs11614913) polymorphism using a polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) approach.

Results:

The frequency of the miR-196a2 (rs11614913) T allele in controls was 0.51 compared with 0.33 in ALL cases. In this study, CC, TC heterozygote and CC/TC genotypes were significantly associated with increase childhood ALL susceptibility compared with the TT wild type (OR =4.321, 95% CI = 2.091-8.930 p=0.000, OR = 2.248, 95% CI =1.103-4.579, p=0.024, OR = 2.921, 95% CI = 1.504-5.673 p=0.001, respectively). However, the miR-196a2 (rs11614913) T>C polymorphism was not associated with demographic data or clinico-pathological data in ALL cases.

Conclusion:

CC, TC and CC+TC genotypes of miR-196a2 (rs11614913) was significantly associated with increased susceptibility in Thai childhood ALL but not with clinical variables.

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.

Association between polymorphisms in interleukins and oral lichen planus: A meta-analysis

BACKGROUND

More and more studies have suggested that single-nucleotide polymorphisms (SNPs) in interleukin (IL) genes are correlated with an increased risk of developing oral lichen planus (OLP). However, these results were inconsistent. Therefore, the aim of this meta-analysis is to retrieve and comprehensively analyze all related clinical studies to investigate the association of ILs gene polymorphisms with the OLP risk.

METHODS

PubMed, Embase, and the Cochrane Library were searched for eligible studies to evaluate the association between IL polymorphisms and the OLP. The odds ratios (ORs) and 95% confidence intervals (CIs) from each study were pooled to estimate the strength of the association. Statistical analyses were performed by using STATA software.

RESULTS

In all 6 studies, including 4 SNPs (IL6-174G/C, IL10-592C/A, IL10-819C/T, and IL10-1082G/A), 362 OLP patients and 622 non-OLP control subjects from five different countries were investigated. As for the IL6-174G/C, IL10-819C/T, and IL10-1082G/A, no evidence was found to support the association between SNP and OLP susceptibility in any genetic models. However, as for IL10-592C/A, a significant relationship between them was identified in all of comparison models (C vs A: OR = 0.724, 95% CI = 0.585-0.897, P = 0.003; CC vs AA: OR = 0.447, 95% CI = 0.276-0.722, P = 0.001; AC vs AA: OR = 0.585, 95% CI = 0.387-0.883, P = 0.011; CC+AC vs AA: OR = 0.544, 95% CI = 0.365-0.809, P = 0.003; CC vs AA+AC: OR = 0.715, 95% CI = 0.515-0.994, P = 0.046).

CONCLUSION

With the presently available evidence, this meta-analysis fails to show the statistical associations between IL6-174G/C, IL10-819C/T, and IL10-1082G/A and OLP susceptibility in any genetic models. However, the A allele and AA genotype in IL10-592C/A polymorphism may increase the risk of OLP. In the future, more well-designed studies with larger sample sizes are needed.

A Variant in the Precursor of MicroRNA-146a is Responsible for Development of Erectile Dysfunction in Patients with Chronic Prostatitis via Targeting NOS1

Background

The morbidity of erectile dysfunction (ED) has been found to be substantially increased in patients with chronic prostatitis (CP). Accumulating evidence shows that single-nucleotide polymorphism (SNP) located in pre-miRNA or mature microRNA may affect the processing of microRNA (miRNA) and alter the expression of the miRNA, as well as its target gene. In this study we investigated the association between rs2910164 G/C polymorphism and risk of ED in patients with CP, as well as the underlying molecular mechanism.

Material/Methods

Computational analysis was used to search for the target of miR-146a, and the luciferase reporter assay system was used to validate NOS1 to be the target gene of miR-146a. We also treated PC-3 cells with miR-146a mimics/inhibitors to verify the negative regulatory relationship between miR-146a and NOS1, and real-time PCR and Western blot analysis were used to estimate the expression of the NOS1 mRNA and miR-146a.

Results

The binding site of miR-146a was found to be located within the 3′-UTR of the NOS1 by searching an online miRNA database (www.mirdb.org), and luciferase reporter assay was done to confirm that NOS1 is a direct target gene of miR-146a. We also found that mRNA and protein expression level of NOS1 in PC-3 cells treated with miR-146a mimics and NOS1 siRNA was substantially down-regulated compared with scramble control, while cells treated with miR-146a inhibitors showed increased expression of NOS1. In addition, 705 people were recruited for our research – 342 CP patients with ED and 363 CP patients without ED – and we found that the presence of minor allele of rs2910164 polymorphism is significantly associated with reduced risk of ED in patients with CP.

Conclusions

The findings indicate a decreased risk of ED in patients with CP who are carriers of miR-146a rs2910164 C allele, and this association might be due to its ability to compromise the expression of miR-146a, and thereby increase the expression of its target gene, NOS1.

A functional variant of miRNA-149 confers risk for allergic rhinitis and comorbid asthma in Chinese children

The prevalence of allergic rhinitis (AR) and asthma has been increasing, and the comorbidity rates of these diseases are very high. Here, 176 AR patients, 124 patients with comorbid AR and asthma (AR-A) and 206 healthy Chinese children as controls were included in a case-control study. Six single-nucleotide polymorphisms (SNPs), miR-146a (rs2910164, rs57095329 and rs6864584), miR-196a2 (rs11614913), miR-499 (rs3746444) and miR-149 (rs2292832), were genotyped. The prevalence of homozygous miR-149 (rs2292832) CC genotype and C allele were considerably increased in AR and AR-A patients, compared with the controls. AR-A group showed higher frequencies of CC genotype and C allele of rs2292832 than AR group. No significant difference in the genotypic and allelic frequencies of other miRNA SNPs was found between the groups. MiR-149 levels in peripheral blood mononuclear cells (PBMCs) were significantly lower in CC (variant type) cases compared with TT (wild-type) cases. In further experiments, PBMCs obtained from the healthy controls with CC, CT and TT genotypes were stimulated by house dust mite extracts, which led to a significant decrease in the levels of miR-149 in PBMCs obtained from CC and TT individuals. This decrease was more pronounced in CC compared with TT cases. Our results demonstrate that miR-149 rs2292832 variant is not only strongly associated with AR and AR-A, but it may lead to an increase in the susceptibility to allergies following the stimulation with an allergen, through the changes in miR149 expression. Additionally, AR patients with CC genotypes were shown to be more susceptible to asthma.

Rapid and ultrasensitive detection of microRNA by target-assisted isothermal exponential amplification coupled with poly (thymine)-templated fluorescent copper nanoparticles

We devised a novel method for rapid and ultrasensitive detection of target microRNA (miRNA) by employing target-assisted isothermal exponential amplification (TAIEA) combined with poly (thymine)-templated fluorescent copper nanoparticles (CuNPs) as signaling probes. The target miRNA hybridizes to the unimolecular template DNA and works as a primer for the extension reaction to form double-stranded product, which consequently generates two nicking endonuclease recognition sites. By simultaneous nicking and displacement reactions, exponential amplification generates many poly (thymine) strands as final products, which are employed for the synthesis of fluorescent CuNPs. Based on the fluorescent signal from CuNPs, target miRNA is detected as low as 0.27 fM around 1 h of total analysis time. The diagnostic capability of this system has been successfully demonstrated by reliably detecting target miRNA from different cell lysates, showing its great potential towards real clinical applications.

A Novel Genetic Variant in Long Non-coding RNA Gene NEXN-AS1 is Associated with Risk of Lung Cancer

Lung cancer etiology is multifactorial, and growing evidence has indicated that long non-coding RNAs (lncRNAs) are important players in lung carcinogenesis. We performed a large-scale meta-analysis of 690,564 SNPs in 15,531 autosomal lncRNAs by using datasets from six previously published genome-wide association studies (GWASs) from the Transdisciplinary Research in Cancer of the Lung (TRICL) consortium in populations of European ancestry. Previously unreported significant SNPs (P value < 1 × 10-7) were further validated in two additional independent lung cancer GWAS datasets from Harvard University and deCODE. In the final meta-analysis of all eight GWAS datasets with 17,153 cases and 239,337 controls, a novel risk SNP rs114020893 in the lncRNA NEXN-AS1 region at 1p31.1 remained statistically significant (odds ratio = 1.17; 95% confidence interval = 1.11-1.24; P = 8.31 × 10-9). In further in silico analysis, rs114020893 was predicted to change the secondary structure of the lncRNA. Our finding indicates that SNP rs114020893 of NEXN-AS1 at 1p31.1 may contribute to lung cancer susceptibility.

Molecular Biomarkers of Colorectal Cancer and Cancer Disparities: Current Status and Perspective

This review provides updates on the efforts for the development of prognostic and predictive markers in colorectal cancer based on the race/ethnicity of patients. Since the clinical consequences of genetic and molecular alterations differ with patient race and ethnicity, the usefulness of these molecular alterations as biomarkers needs to be evaluated in different racial/ethnic groups. To accomplish personalized patient care, a combined analysis of multiple molecular alterations in DNA, RNA, microRNAs (miRNAs), metabolites, and proteins in a single test is required to assess disease status in a precise way. Therefore, a special emphasis is placed on issues related to utility of recently identified genetic and molecular alterations in genes, miRNAs, and various "-omes" (e.g., proteomes, kinomes, metabolomes, exomes, methylomes) as candidate molecular markers to determine cancer progression (disease recurrence/relapse and metastasis) and to assess the efficacy of therapy in colorectal cancer in relation to patient race and ethnicity. This review will be useful for oncologists, pathologists, and basic and translational researchers.

Association of single nucleotide polymorphisms in Pre-miR-27a, Pre-miR-196a2, Pre-miR-423, miR-608 and Pre-miR-618 with breast cancer susceptibility in a South American population

Background

MicroRNAs (miRNAs) are a novel class of endogenous, non-coding, single-stranded RNAs capable of regulating gene expression by suppressing translation or degrading mRNAs. Single nucleotide polymorphisms (SNP) can alter miRNA expression, resulting in diverse functional consequences. Previous studies have examined the association of miRNA SNPs with breast cancer (BC) susceptibility. The contribution of miRNA gene variants to BC susceptibility in South American women had been unexplored. Our study evaluated the association of the SNPs rs895819 in pre-miR27a, rs11614913 in pre-miR-196a2, rs6505162 in pre-miR-423, rs4919510 in miR-608, and rs2682818 in pre-mir-618 with familial BC and early-onset non-familial BC in non-carriers of BRCA1/2 mutations from a South American population.

Results

We evaluated the association of five SNPs with BC risk in 440 cases and 807 controls. Our data do not support an association of rs11614913:C > T and rs4919510:C > G with BC risk. The rs6505162:C > A was significantly associated with increased risk of familial BC in persons with a strong family history of BC (OR = 1.7 [95 % CI 1.0–2.0] p = 0.05). The rs2682818:C > A genotype C/A is associated with an increased BC risk in non-familial early-onset BC. For the rs895819:A > G polymorphism, the genotype G/G is significantly associated with reduced BC risk in families with a moderate history of BC (OR = 0.3 [95 % CI 0.1–0.8] p = 0.01).

Conclusions

The contribution of variant miRNA genes to BC in South American women had been unexplored. Our findings support the following conclusions: a) rs6505162:C > A in pre-miR-423 increases risk of familial BC in families with a strong history of BC; b) the C/A genotype at rs2682818:C > A (pre-miR-618) increases BC risk in non-familial early-onset BC; and c) the G/G genotype at rs895819:A > G (miR-27a) reduces BC risk in families with a moderate history of BC.

Clinical Significance of miR-149 in the Survival of Patients with Laryngeal Squamous Cell Carcinoma

MicroRNAs (miRNAs) play critical roles in the progression of laryngeal cancer (LC). In this study, we aimed to investigate whether miR-149 is associated with the prognosis of patients with LC. A total of 97 laryngeal squamous cell carcinoma patients who underwent tumor resection were included in our follow-up study. In vitro studies was performed in cancer cell line Hep-2 to explore the antitumor role of miR-149 in LC. We found that the expression of miR-149 was significantly lower in tumor tissues, compared with vocal cord polyp tissues (P < 0.05). Kaplan-Meier analysis revealed that miR-149 expression status is significantly associated with survival duration (log rank test, P < 0.05), and multivariate Cox regression analysis revealed that patients with low miR-149 expression had shorter survival times compared with patients with high miR-149 expression. In vitro studies revealed that the exogenous expression of miRNA-149 inhibits the proliferation of human Hep-2 cells and induces cell apoptosis. Our study suggests that miR-149 expression in laryngeal squamous cell carcinoma tissues is critically associated with the prognosis of patients, and the ectopic expression of miR-149 in Hep-2 cells inhibits proliferation and cell cycle progression.

MiR-196a2 rs11614913 T>C Polymorphism is Associated with an Increased Risk of Tetralogy of Fallot in a Chinese Population

BACKGROUND

MicroRNAs (miRNAs) are a family of endogenous, small, noncoding single-stranded RNAs that act as post-transcriptional gene regulatory elements. MiRNA polymorphisms may be associated with susceptibility to congenital heart disease (CHD). The aim of this study was to evaluate the impact of miRNA single nucleotide polymorphisms (SNPs) on CHD susceptibility.

METHODS

We genotyped two functional SNPs, miR-196a2 rs11614913 and miR-146a rs2910164, in a case-control cohort of 173 Chinese patients with tetralogy of Fallot (TOF) and 207 non-CHD controls.

RESULTS

When the miR-196a2 rs11614913 TT homozygote genotype was used as the reference group, the TC genotype was not associated with an increased risk of TOF. The CC genotype was associated with a borderline significantly increased risk for TOF. In the recessive model, when the miR-196a2 rs11614913 TT/TC genotypes were used as the reference group, the CC homozygote genotype was associated with a significantly increased risk of TOF (OR = 1.96, 95% CI = 1.18-3.25, p = 0.01). The miR-146a rs2910164 C>G polymorphism was not associated with developing TOF.

CONCLUSIONS

Our findings suggested that the miR-196a2 rs11614913 T>C polymorphism may play a role in the development of TOF. Future larger studies that include populations of other ethnicities are required to confirm these findings.

KEY WORDS

Congenital heart disease; MiRNA; Molecular epidemiology; Polymorphisms; Tetralogy of Fallot.

The Mechanism and Function of Epigenetics in Uterine Leiomyoma Development

Uterine leiomyomas, also known as uterine fibroids, are the most common pelvic tumors, occurring in nearly 70% of all reproductive-aged women and are the leading indication for hysterectomy worldwide. The development of uterine leiomyomas involve a complex and heterogeneous constellation of hormones, growth factors, stem cells, genetic, and epigenetic abnormalities. An increasing body of evidence emphasizes the important contribution of epigenetics in the pathogenesis of leiomyomas. Genome-wide methylation analysis demonstrates that a subset of estrogen receptor (ER) response genes exhibit abnormal hypermethylation levels that are inversely correlated with their RNA expression. Several tumor suppressor genes, including Kruppel-like factor 11 (KLF11), deleted in lung and esophageal cancer 1 (DLEC1), keratin 19 (KRT19), and death-associated protein kinase 1 (DAPK1) also display higher hypermethylation levels in leiomyomas when compared to adjacent normal tissues. The important role of active DNA demethylation was recently identified with regard to the ten-eleven translocation protein 1 and ten-eleven translocation protein 3-mediated elevated levels of 5-hydroxymethylcytosine in leiomyoma. In addition, both histone deacetylase and histone methyltransferase are reported to be involved in the biology of leiomyomas. A number of deregulated microRNAs have been identified in leiomyomas, leading to an altered expression of their targets. More recently, the existence of side population (SP) cells with characteristics of tumor-initiating cells have been characterized in leiomyomas. These SP cells exhibit a tumorigenic capacity in immunodeficient mice when exposed to 17β-estradiol and progesterone, giving rise to fibroid-like tissue in vivo. These new findings will likely enhance our understanding of the crucial role epigenetics plays in the pathogenesis of uterine leiomyomas as well as point the way to novel therapeutic options.

Association between the rs11614913 variant of miRNA-196a-2 and the risk of epithelial ovarian cancer

Polymorphisms in microRNA (miR) genes and their target sites are a distinct classification of variation in the human genome, which are rapidly being identified and investigated in human cancer. A polymorphism in the miR-196a-2 locus has demonstrated significant associations with various types of cancer, including lung, breast, esophageal and gastric tumors. However, miR-196a-2 has not been fully explored in ovarian cancer, which shares similar biological characteristics with other types of cancer. Therefore, the present study aimed to elucidate the association between a single nucleotide polymorphism (SNP) in the mature sequence of miR-196a-2 (rs11614913, T/C) and the clinical features of 479 Chinese patients with epithelial ovarian cancer (EOC). In addition, the biological significance of this polymorphism was investigated in the OVCAR3 ovarian cancer cell line. Risk association was evaluated in 479 cases of EOC patients and 431 controls. SNPs were analyzed by using polymerase chain reaction based restriction fragment length polymorphism assay. miR-196a expression was evaluated with reverse transcription polymerase chain reaction. The influence of miR-196a-2 rs11614913 T/C on EOC cell migration and invasion ability was further investigated in vitro. The results revealed significant differences in the homozygous CC genotype distribution in patients with EOC (n=479), compared with that of the control subjects (n=431; P=0.026). Analysis of the association between genotype and the risk of EOC revealed that individuals who carried the homozygous CC genotype were 1.34-fold more susceptible to EOC, compared with those carrying the wild-type TT and heterozygous CT genotypes [odds ratio, 1.34; 95% confidence interval, 1.04-2.17; P=0.023]. In addition, the role of this polymorphism in the production of mature miR-196a was investigated. Significantly enhanced production of mature miR-196a was revealed in the C-allelic compared with that of the T-allelic miR-196a-2 precursor (P<0.05). Further examination indicated that miR-196a significantly promoted cell migration and invasion ability in the human OVCAR3 ovarian cell line (P<0.05). In conclusion, the results indicated that the miR-196a-2 rs11614913 CC genotype may increase the risks of ovarian cancer by affecting the expression of mature miR-196a and enhancing cell migration/invasion. The current results provided evidence that the T>C polymorphism in the miR-196a-2 precursor may influence tumorigenesis and metastasis in EOC, and suggested that the functional SNP rs11614913 in the promoter region of pri-miR-196a-2 may be a potential indicator of EOC susceptibility in the population analyzed.

The CDKN2A-CDKN2B rs4977756 polymorphism and glioma risk: a meta-analysis

The association between the rs4977756 single nucleotide polymorphism (SNP) and glioma risk has been studied, but these studies have yielded conflicting results. In order to explore this association, we performed a meta-analysis. A comprehensive literature search was performed using PubMed and EMBASE database. Six articles including 12 case-control studies in English with 12022 controls and 6871 cases were eligible for the meta-analysis. Subgroup analyses were conducted by ethnicity and source of controls. Our meta-analysis found that rs4977756 polymorphism was associated with glioma risks in homozygote, heterozygote, dominant, recessive and additive genetic models (GG versus AA: OR=1.55, 95% CI=1.42-1.69, Ph=0.996, I(2)=0.0%; AG versus AA: OR=1.20, 95% CI=1.12-1.28, Ph=0.934, I(2)=0.0%; recessive model: OR=1.39, 95% CI=1.28-1.50, Ph=0.995, I(2)=0.0%; dominant model: OR=1.29, 95% CI=1.21-1.37, Ph=0.923, I(2)=0.0%; additive model: OR=1.24, 95% CI=1.19-1.30, Ph=0.966, I(2)=0.0%). Moreover, our results suggested that CDKN2A-CDKN2B rs4977756 polymorphism was associated with a notable increased risk of glioma in Europeans. However, in Asians, we could not come to a conclusion because of lack of studies. Sensitivity analysis showed the omission of any study made no significant difference. No evidence of publication bias was produced. Our meta-analysis suggested that rs4977756 polymorphism was associated with increased risk of glioma. Moreover, additional studies should be further investigated to draw a more accurate conclusion.

Overexpression of microRNA‑125a‑3p effectively inhibits the cell growth and invasion of lung cancer cells by regulating the mouse double minute 2 homolog/p53 signaling pathway

MicroRNAs (miRs) are a family of small non-coding RNAs that are 21‑24 nucleotides in length. Decreased expression of hsa‑miR‑125a‑3p is observed in a number of patients with non‑small cell lung cancer; however, it is not clear how this miRNA regulates the growth and invasion of lung tumor cells. The aim of the present study was to identify the function of hsa‑miR‑125a‑3p in the growth and invasion of lung cancer cells. The expression of hsa‑miR‑125a‑3p in the A549, NCI‑H460 and SPCA‑1 lung cancer cell lines was analyzed by reverse transcription‑quantitative polymerase chain reaction and the human bronchiolar epithelium cell line (HBE) was used as a control. The results demonstrated that the expression of hsa‑miR‑125a‑3p was significantly lower in NCI‑H460, A549 and SPCA‑1 cells, compared with that in HBE cells. Overexpression of sense miR‑125a‑3p in the A549 lung cancer cell line inhibited cell proliferation for 5‑7 days (P<0.01), and transfection of antisense miR‑125a‑3p did not suppress the cell growth of the lung cancer cells. In addition, overexpression of miR‑125a‑3p in the NCI‑H460 lung cancer cell line markedly induced cell apoptosis, which was detected by fluorescence‑activated cell sorting with annexin V‑fluorescein isothiocyanate/propidium iodide staining. The results of the Transwell migration assay also revealed that transfection of miR‑125a‑3p resulted in decreased migration of lung cancer tumor cells. The pro‑apoptotic gene p53 expression was detected by western blot analysis. The results revealed that the expression of mouse double minute (MDM)‑2 homolog, the principal cellular antagonist of p53, was decreased and p53 expression was upregulated in sense has‑miR‑125a‑3p transfected A549 cells. This was consistent with that observed in NCI‑H460 cells, suggesting that hsa‑miR‑125a‑3p may be involved in the regulation of the MDM2/p53 signaling pathway in lung cancer cells. In conclusion, overexpression of hsa‑miR‑125a‑3p significantly inhibited the proliferation and invasion of lung cancer cells, which may aid in determining the mechanisms underlying the development of lung cancer.

Downregulation of Plasma MiR-142-3p and MiR-26a-5p in Patients With Colorectal Carcinoma

Background:

Colorectal cancer is one of the most commonly diagnosed cancers and cancer- related death worldwide. Identification of new specific biomarkers could be helpful to detection of this malignancy. Altered plasma microRNA expression has been identified in many cancers, including colorectal cancer.

Objectives:

The main objective of this study was to identify the circulating microRNAs with the most expression changes in colorectal cancer patients compared with neoplasm free healthy individuals.

Materials and Methods:

MicroRNA expression profiling was performed on plasma samples of 37 colorectal cancer patients and 8 normal subjects using microRNA microarray. Quantitative real-time reverse transcription polymerase chain reaction was used to validate the two selected altered microR NAs. Plasma samples from 61 colorectal cancer patients and 24 normal subjects were used in our validation study.

Results:

In profiling study we found a panel of six plasma microRNAs with significant downregulation. MicroRNA-142-3p and microRNA-26a-5p were selected and validated by polymerase chain reaction. Our results demonstrated that expression levels of plasma microRNA-142-3p and microRNA-26a-5p were significantly downregulated in patients with colorectal cancer when compared to control group.

Conclusions:

Our findings suggest that downregulation of plasma microRNA-142-3p and microRNA-26a-5p might serve as novel noninvasive biomarkers in the diagnosis of colorectal cancer, although more studies are needed to highlight the theoretical strengths.

Quantitative Assessment of the Association between Genetic Variants in MicroRNAs and Colorectal Cancer Risk

Background. The associations between polymorphisms in microRNAs and the susceptibility of colorectal cancer (CRC) were inconsistent in previous studies. This study aims to quantify the strength of the correlation between the four common polymorphisms among microRNAs (hsa-mir-146a rs2910164, hsa-mir-149 rs2292832, hsa-mir-196a2 rs11614913, and hsa-mir-499 rs3746444) and CRC risk. Methods. We searched PubMed, Web of Knowledge, and CNKI to find relevant studies. The combined odds ratio (OR) with 95% confidence interval (95% CI) was used to estimate the strength of the association in a fixed or random effect model. Results. 15 studies involving 5,486 CRC patients and 7,184 controls were included. Meta-analyses showed that rs3746444 had association with CRC risk in Caucasians (OR = 0.57, 95% CI = 0.34–0.95). In the subgroup analysis, we found significant associations between rs2910164 and CRC in hospital based studies (OR = 1.24, 95% CI = 1.03–1.49). rs2292832 may be a high risk factor of CRC in population based studied (OR = 1.18, 95% CI = 1.08–1.38). Conclusion. This meta-analysis showed that rs2910164 and rs2292832 may increase the risk of CRC. However, rs11614913 polymorphism may reduce the risk of CRC. rs3746444 may have a decreased risk to CRC in Caucasians.

Associations of polymorphisms in microRNAs with female breast cancer risk in Chinese population

Polymorphisms in microRNA (miRNA) have been discussed to be associated with breast cancer risk; however, the conclusions were always inconsistent in different ethnicities. This case-control study enrolled 450 breast cancer cases, and 450 health controls was carried out to investigate the association between six polymorphisms in miRNAs and breast cancer risk. Sequenom MassARRAY was used to detect the polymorphisms in miRNAs, and the immunohistochemistry assay was applied to detect the expression of estrogen receptor (ER) and progesterone receptor (PR) in cancer tissue. The data showed that the 3746444 GG was associated with increased breast cancer risk (adjusted odds ratio (OR) = 1.71, 95 % confidence interval (CI) = 1.16-2.52) and that rs2292832 CC (adjusted OR = 0.54, 95 % CI = 0.34-0.85) was associated with decreased breast cancer risk. In addition, menopausal status subgroup analysis revealed that rs3746444 GG (adjusted OR = 2.34, 95 % CI = 1.31-4.15) and GA/GG (adjusted OR = 1.60, 95 % CI = 1.08-2.37) genotypes were associated with increased breast cancer risk for the subgroup of women with premenopausal status, respectively. Moreover, rs2910164 GG (adjusted OR = 1.84, 95 % CI = 1.07-3.15) and CG/GG (adjusted OR = 1.47, 95 % CI = 1.01-2.15) genotypes were associated with increased breast cancer risk in the postmenopausal status subcohort, respectively. Furthermore, rs3746444 AG (adjusted OR = 1.61, 95 % CI = 1.06-2.45) and AG/GG (adjusted OR = 1.49, 95 % CI = 1.02-2.18) genotypes were observed to be associated with increased risk of lymph node involvement and breast cancer with negative PR expression, separately. In short, rs3746444 was associated with breast cancer risk, especially for women with premenopausal status, and rs2910164 CG and CG/GG genotypes were associated with breast cancer risk for the women with premenopausal status.

Association of Pre-miR-146a rs2910164 Polymorphism with Papillary Thyroid Cancer

The incidence rate of papillary thyroid cancer (PTC) has increased over the past decades, but the pathogenesis remains unclear. rs2910164, located in pre-miR-146a, has been studied in PTCs with different ethnicity, but the results were inconsistent. Here we evaluate the association between rs2910164 polymorphism and PTC and investigate the effect of this polymorphism on patients' clinicopathological characteristics. 1238 PTC patients and 1275 controls, all Han population, from Northern China, were included in our study. rs2910164 was genotyped using Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF-MS). Analysis of inheritance model was performed using the SNPStats program. Strength of association was assessed by odds ratio (OR) and 95% confidence interval (CI). Overall, no statistical difference in rs2910164 genotype distribution and allelic frequencies between cases and controls was found, and patients with different genotypes had similar clinicopathological characteristics in terms of stage, location, concurrent of benign thyroid tumor, and thyroiditis, while, as the number of G alleles increased, proportion of patients aged ≥45 years and those without metastasis increased (P trend < 0.001 and P trend = 0.003, resp.). However, no association remained significant after Bonferroni correction under any model of inheritance. Our results suggest no association between rs2910164 polymorphism with PTC and patients' clinicopathological characteristics.

miR-124 rs531564 polymorphism influences genetic susceptibility to cervical cancer

Cervical cancer is the fourth most common cancer among women worldwide. It most frequently results from human papillomavirus (HPV) infection; however, recent evidence suggests that there may be underlying genetic factors, specifically in regions encoding microRNAs, dictating susceptibility to cervical cancer. This study investigated the relationship between the miR-124 rs531564 gene polymorphism and genetic susceptibility to cervical cancer in Chinese Han women. From January 2011 to July 2013, 158 Chinese Han cervical cancer patients and 260 healthy Chinese Han females were recruited to provide blood samples. The miR-124 rs531564 (C > G) polymorphism genotype was determined by polymerase chain reaction-based ligase detection reaction (PCR-LDR), and multivariate logistic regression analysis was used to deduce the relationship between the miR-124 rs531564 variant and cancer diagnosis. As expected, the incidence of HPV infection in cervical cancer patients was significantly higher than controls (P < 0.001). Logistic regression analysis showed that a CG genotype was associated with reduced risk of cervical cancer compared to the wildtype CC genotype (OR = 0.46, 95% CI: 0.19-0.92); the findings were similar when the variant genotypes were combined (CG + GG; OR = 0.42, 95% CI: 0.17-0.86). The G allele was associated with reduced risk of cervical cancer (OR = 0.45, 95% CI: 0.14-0.89) particularly among women over age 40 (OR = 0.31, 95% CI: 0.12-0.84), as well as reduced risk of HPV infection (OR = 0.59, 95% CI: 0.28-0.93). These results further support a role for genetic susceptibility in miR-124 rs531564 in determining the risk of cervical cancer in Chinese Han women.

Effect of a common genetic variant microRNA-146a rs2910164 on colorectal cancer: a meta-analysis

OBJECTIVE

There is emerging evidence that the microRNA-146a (miR-146a) rs2910164 polymorphism might be associated with the susceptibility to colorectal cancer (CRC). However, previous published studies have failed to achieve a definitive conclusion. We aimed to address this issue in an updated meta-analysis.

METHODS

A comprehensive literature search was conducted in PubMed, Embase, China BioMedicine, the Cochrane Library and Google Scholar to identify eligible studies. Case-control studies written in English that evaluated the association between miR-146a polymorphism and CRC were included. Odds ratio and 95% confidence interval were calculated in the quantitative synthesis.

RESULTS

Overall seven case-control studies including a total of 2978 cases and 3576 cancer-free or healthy controls were enrolled in the meta-analysis. The results indicated that there was no association between miR-146a G/C rs2910164 polymorphism and CRC risk either in the overall analysis or among Asians, when stratified on the basis of ethnicity.

CONCLUSION

miR-146a G/C genetic polymorphism was not related to the susceptibility to CRC.

miR-224 overexpression is a strong and independent prognosticator of short-term relapse and poor overall survival in colorectal adenocarcinoma

Colorectal adenocarcinoma constitutes the most frequent form of colorectal cancer and a serious cause of cancer-related deaths. The expression of multiple miRNAs, including miR-224, is deregulated in colorectal adenocarcinoma. The aim of this study was the investigation of the prognostic value of miR-224 in colorectal adenocarcinoma. For this purpose, total RNA was isolated from 115 colorectal adenocarcinomas and 66 adjacent non-cancer mucosae. Total RNA (2 µg) was polyadenylated and reverse transcribed. A quantitative PCR method based on SYBR-Green chemistry was developed and applied for the quantification of miR-224 levels, followed by extensive biostatistical analysis. miR-224 levels in malignant colorectal adenocarcinomas ranged between 1.81 and 187.75 RQU (miR-224 copies/1,000 SNORD48 copies) with a median of 34.27, and were significantly elevated, compared to miR-224 levels in adjacent non-cancer mucosae (p<0.001). Enhanced miR-224 expression constitutes a rather strong prognosticator in colorectal adenocarcinoma, predicting short-term relapse and poor overall survival in these patients (p=0.012 and p=0.005, respectively), independent of established clinicopathological parameters. In conclusion, miR-224 is significantly upregulated in malignant colorectal tumors compared to adjacent non-cancer mucosae, and its enhanced expression constitutes an independent predictor of short-term relapse and poor overall survival in colorectal adenocarcinoma patients.

MiR-146a rs2910164 G/C polymorphism and gastric cancer susceptibility: a meta-analysis

Background

Evidence has shown that single nucleotide polymorphism located in pre-miRNA or mature microRNA may modify various biological processes and affect the processing of carcinogenesis. Published results about the association between miR-146a rs2910164 G/C polymorphism and human gastric cancer susceptibility are inconclusive. The aim of this study was to acquire a more precise effect of the association between the miR-146a rs2910164 polymorphism and gastric risk by meta-analysis.

Methods

Eligible genetic association studies were searched from PubMed, Web of Knowledge and Chinese Biomedicine Database on human subject. Quantitative data synthesis was conducted for the associations of miR-146a rs2910164 G/C polymorphism with susceptibility to gastric cancer.

Results

Nine eligible studies that included a total of 3,885 gastric cancer patients and 5,396 controls were identified in the present meta-analysis. The overall OR indicated a potential association between rs2910164 polymorphism and GC but the effect was not statistically significant (GG vs. CG/CC: OR = 1.076, 95% CI 0.925-1.251, P = 0.342). When stratifying for population, the result showed that miR-146a rs2910164 GG genotype was associated with increased gastric cancer risk among Chinese in recessive model (GG vs. CG/CC: OR = 1.171, 95% CI 1.050-1.306, P = 0.005). Besides, no significant difference was found in gender, smoking, location, metastasis of lymph node and Laurèn’s classification.

Conclusions

The present meta-analysis suggests an increased risk between miR-146a rs2910164 GG genotype and gastric cancer susceptibility in Chinese based on published literatures.

MicroRNA polymorphisms as markers of risk, prognosis and treatment response in hematological malignancies

MicroRNA dysregulation is a common event in hematological malignancies. Apart from genomic and epigenetic alterations, miRNA networks may be disturbed by polymorphisms in the miRNA regulatory pathway (miRSNPs). In this review we provide an overview of three categories of miRSNPs: (1) SNPs in genes involved in miRNA biogenesis and processing; (2) SNPs in miRNA genes; and (3) SNPs in miRNA binding sites in target genes and discuss their potential role as markers of disease risk, prognosis and treatment response in hematological cancers. Although so far only the tip of the iceberg has been touched, studies of polymorphisms in the miRNA regulatory pathways have already provided some clues for the mechanisms of miRNA dysregulation in cancer and open new perspectives in the management of hematological malignancies.

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

Colorectal cancer (CRC) is one of the most common cancers worldwide with high mortality rates. MicroRNAs (miRNAs) have an established role in the development of different cancers. Single nucleotide polymorphisms (SNPs) in miRNA related genes were linked with various gastrointestinal malignancies. However, the data on association between miRNA SNPs and CRC development are inconsistent. The aim of the present study was to evaluate the association between miRNA-related gene polymorphisms (miR-27a, miR-146a, miR-196a-2, miR-492 and miR-608) and the presence of CRC in European population. Gene polymorphisms were analyzed in 621 subjects (controls: n = 428; CRC: n = 193). 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. Overall, all genotypes and alleles of miRNA SNPs were distributed equally between control and CRC groups. We observed a tendency for miR-146a C allele to be associated with lower risk of CRC when compared to G allele, however, the difference did not reach the adjusted P-value (odds ratio (OR) = 0.68, 95% confidence interval (CI) 0.49–0.95, P = 0.025). In conclusion, gene polymorphisms of miR-27a, miR-146a, miR-196a-2, miR-492, miR-492a and miR-608 were not associated with the presence of CRC in European subjects.

Common polymorphisms in MIR146a, MIR128a and MIR27a genes contribute to neuropathy susceptibility in type 2 diabetes

Diabetic polyneuropathy (DPN) and cardiovascular autonomic neuropathy (CAN) are common type 2 diabetes complications with a large inter-individual variability in terms of clinical manifestations and severity. Our aim was to evaluate a possible involvement of genetic polymorphisms in miRNA regions in the susceptibility to DPN and CAN. Nine polymorphisms in miRNA genes were studied in a sample of 132 type 2 diabetes patients (T2D) analysed for DPN and 128 T2D patients analysed for CAN. A genotype-phenotype correlation analysis was performed. The T allele of rs11888095 single nucleotide polymorphism (SNP) in MIR128a was significantly associated with a higher risk (ORadj = 4.89, P adj = 0.02), whereas the C allele of rs2910164 SNP in MIR146a was associated with a lower risk to develop DPN (ORadj = 0.49, P adj = 0.09), respectively. A multivariate logistic regression analysis confirmed that both SNPs contribute to DPN (p < 0.001 and p = 0.01 for MIR128a and MIR146a, respectively). MIR128a SNP significantly contributed also to DPN score (p = 0.026). Rs895819 SNP in MIR27a was significantly associated with a higher risk to develop early CAN (P adj = 0.023 and ORadj = 3.43). The rs2910164 SNP in MIR146a showed a protective effect respect to early CAN (P adj = 0.052, ORadj = 0.32) and to confirmed CAN (P adj = 0.041, ORadj = 0.13). The same SNP resulted significantly associated with a lower CAN score and a higher E/I (p = 0.002 and p = 0.003, respectively). In conclusion, we described associations of MIR128a and MIR146a SNPs with DPN susceptibility and of MIR146a and MIR27a SNPs with CAN susceptibility. This is the first study showing that genetic variability in miRNA genes could be involved in diabetic neuropathies susceptibility.

An miR-143 promoter variant associated with essential hypertension

MicroRNAs like miR-143 are increasingly linked to disease pathogenesis. miR-143 is enriched in vascular smooth muscle, and several single nucleotide polymorphisms have been identified in this miRNA. The aim of the current study was to explore a potential correlation between a polymorphism in the miR-143 promoter region, rs4705342, and essential hypertension (EH). Genotyping for miR-143 rs4705342 was performed from blood samples of 156 EH patients (case group) and 187 healthy individuals (control group) using a TaqMan assay. Participant demographic and clinical characteristics were also collected. Logistic regression was used to identify an association between genotype and EH, and odds ratios of EH risk were also determined. Frequencies of the CC, CT, and TT genotypes differed significantly between case (7.7%, 40.4%, 51.9%) and control (15.0%, 48.1%, 36.9%) groups (χ(2) = 9.400, P = 0.009). Further, the frequency of the C allele was lower in the case group than in the control group (27.9% vs. 39.0%, P = 0.002). Compared with those having the TT genotype, patients carrying the CC and CT genotypes had a significantly reduced risk for EH (OR = 0.541, 95% CI = 0.351-0.834, P = 0.005), particularly for females, nonsmokers, and those not consuming alcohol (P < 0.05). Thus, the rs4705342 polymorphism in the miR-143 appears to be associated with essential hypertension, and further study is needed to understand the molecular mechanism producing this effect.

The Catechol-O-Methyltransferase Val158Met Polymorphism Contributes to the Risk of Breast Cancer in the Chinese Population: An Updated Meta-Analysis

PURPOSE

Catechol-O-methyltransferase (COMT) enzyme plays a central role in estrogen-induced carcinogenesis. Emerging evidence from association studies has revealed that the functional Val158Met polymorphism (rs4680 G>A) of the Catechol-O-methyltransferase gene (COMT) has been implicated in susceptibility to breast cancer in the Chinese population, while results of individual published studies remain inconclusive and inconsistent. To assess this association in the Chinese population, a meta-analysis was performed.

METHODS

Eligible studies were searched on MEDLINE, Embase, Cochrane Library, China National Knowledge Infrastructure, and the Chinese Biomedicine Database. Odds ratios (ORs) with their corresponding 95% confidence intervals (CIs) were pooled to assess the association between COMT polymorphisms and the risk of breast cancer using RevMan 5.2 and Stata 12.0 software.

RESULTS

The meta-analysis included 14 eligible studies, with a total of 4,626 breast cancer cases and 5,637 controls. Overall, the COMT Val158Met polymorphism (rs4680 G>A) was significantly associated with an increased risk of breast cancer in several genetic models (A/A vs. G/G: OR, 1.59, 95% CI, 1.12-2.27; A/A vs. G/A+G/G: OR, 1.62, 95% CI, 1.14-2.29; A vs. G: OR, 1.15, 95% CI, 1.00-1.32), and a subgroup analysis according to menopausal status showed that this association was especially evident among premenopausal Chinese women (A/A vs. G/G: OR, 1.87, 95% CI, 0.99-3.54; A/A vs. G/A+G/G: OR, 1.94, 95% CI, 1.03-3.63).

CONCLUSION

The results of this meta-analysis indicated that COMT Val158Met variants contribute to breast cancer susceptibility in the Chinese population, particularly among premenopausal women.

Regulatory effects of miRNA on gastric cancer cells

The present study aimed to screen the regulatory mechanism of microRNA (miR/miRNA) typing on gastric cancer cells in gastric cancer tissues. In total, 46 patients who underwent gastric resection in Xiangya Hospital of Central-South University (Changsha, Hunan, China) between January and December 2012 were selected. Gastric cancer cells were obtained for RNA extraction, and miRNAs were detected by quantitative polymerase chain reaction. Compared with the expression levels in the normal gastric mucosa, the expression levels of miR-9, miR-433, miR-19b and miR-370 were downregulated; the differences was statistically significant, except for miR-19b (P<0.05). miRNAs play a regulative role in the occurrence and development of gastric cancer, and changes in their expression provide a basis for the diagnosis of this disease.

Up-regulation of miR-630 in clear cell renal cell carcinoma is associated with lower overall survival

INTRODUCTION

MicroRNAs (miRNAs) are noncoding RNAs that regulate multiple cellular processes during cancer progression. MiR-630 has recently been identified to be involved in tumorigenesis of several cancers such as lung cancer and gastric cancer. However, the regulation of miR-630 in clear cell renal cell carcinoma (ccRCC) has not yet been reported before.

METHODS

Expression of miR-630 was evaluated by quantitative real-time PCR in tumour and their normal matched tissues in n = 92 ccRCC patients, and its association with overall survival of patients was analyzed by statistical analysis.

RESULTS

The expression level of miR-630 was significantly higher in renal cancer in comparison to normal matched tissue (P < 0.05). It is also proved that miR-630 expression was to be associated with renal cancer histologic grade, lymphnode metastasis, distant metastasis (P < 0.05). In addition, the Kaplan-Meier survival curves revealed that high miR-630 expression was associated with poor prognosis in ccRCC patients. miR-630 expression was an independent prognostic marker of overall ccRCC patient survival in a multivariate analysis.

CONCLUSIONS

The study proves for the first time that miR-630 is upregulated in a majority of ccRCC patients. It also shows that miR-630 expression is an independent prognostic factor for patients with renal cancer, which might be a potential valuable biomarker for ccRCC.

A new polymorphism biomarker rs629367 associated with increased risk and poor survival of gastric cancer in chinese by up-regulated miRNA-let-7a expression

Background

Variant in pri-miRNA could affect miRNA expression and mature process or splicing efficiency, thus altering the hereditary susceptibility and prognosis of cancer. We aimed to assess miRNA-let-7 single nucleotide polymorphisms (SNP) associated with the risk and prognosis of gastric cancer (GC) as predicting biomarkers, and furthermore, its possible mechanisms.

Methods

A two-stage case-control study was designed to screen four miRNA SNPs (pri-let-7a-2 rs629367 and rs1143770, pri-let-7a-1 rs10739971, pri-let-7f-2 rs17276588) in 107 GC patients, 107 atrophic gastritis (AG), and matched 124 controls using PCR-RFLP. Two promising SNPs were validated in another independent 1949 samples (including 579 gastric cancer patients, 649 atrophic gastritis and 721 controls) using Sequenom MassARRAY platform and sequencing.

Results

We found that pri-let-7a-2 rs629367 CC variant genotype was associated with increased risks of gastric cancer and atrophic gastritis by 1.83-fold and 1.86-fold, respectively. For gastric cancer prognosis, patients with rs629367 CC genotype had significantly poorer survival than patients with AA genotype (log-rank P = 0.004). We further investigated the let-7a expression levels in serum and found that let-7a expression elevated gradually for rs629367 AA, CA, CC genotype in the atrophic gastritis group (P = 0.043). Furthermore, we confirmed these findings in vitro study by overexpressing let-7a carrying pri-let-7a-2 wild-type A or polymorphic-type C allele (P<0.001).

Conclusions

pri-let-7a-2 rs629367 CC genotype could increase the risks of gastric cancer as well as atrophic gastritis and was also associated with poor survival of gastric cancer, which possibly by affecting the mature let-7a expression, and could serve as a predicting biomarker for high-risk and poor prognosis of gastric cancer.

Association between rs2910164, a single nucleotide polymorphism in miRNA-146a, and susceptibility to hepatocellular carcinoma: A Meta-analysis

AIM: To accurately evaluate the association between the miRNA-146a rs2910164 polymorphism and susceptibility to hepatocellular carcinoma by Meta-analysis.

METHODS: An electronic search of PubMed, Excerpta Medica Database (Embase), Chinese Biomedical Literature Database (CBM), the Cochrane Library, Weipu and Wanfang database for relevant articles was conducted. The difference of miRNA-146a rs2910164 genotypes (G vs C, GG vs CC, GG vs GC, GC vs CC, GG + GC vs CC, and GG vs GC + CC) between cases and controls was analyzed through Meta-analysis.

RESULTS: A total of 8 studies involving 5968 subjects were found to be eligible for our meta-analysis. There was evidence of association between miR-146a rs2910164 polymorphism and the risk of hepatocellular carcinoma in the overall analysis (GC vs CC: OR = 1.15; 95%CI: 1.02-1.92, P = 0.02; GG + GC vs CC: OR = 1.15; 95%CI: 1.03-1.29, P = 0.01). In the subgroup analysis by ethnicity, similar results could be found among Asians (GC vs CC: OR = 1.15, 95%CI = 1.02-1.29, P = 0.02).

CONCLUSION: Our Meta-analysis suggested that the rs2910164 polymorphism in miR-146a was more likely to be associated with hepatocellular carcinoma risk. Besides, the CC genotype of rs2910164 might be associated with a reduced risk for hepatocellular carcinoma.

Association between apolipoprotein E genotype and cancer susceptibility: a meta-analysis

BACKGROUND

Apolipoprotein E (ApoE), a protein primarily involved in lipoprotein metabolism, occurs in three isoforms (E2, E3 and E4). Studies evaluating the association between APOE genotype and incidence of malignancies have given inconclusive results.

OBJECTIVE

The objective of the present study was to analyze the association between APOE genotype and incidence of cancer by a meta-analysis.

METHODS

We conducted a literature search in the electronic databases for studies with information on APOE genotype in malignancies. Sixteen studies (14 case-control and 2 cohort; 77,970 controls and 12,010 cases) were included for the present meta-analysis. Pooled odds ratios (OR) with 95 % confidence intervals (CI) were calculated assuming a random-effect model for all the genotypes and alleles. Subgroup analyses based on study design, ethnicity of populations, site of cancer and source of controls were performed as a post hoc measure. Appropriate tests to detect heterogeneity, publication bias and sensitivity were done at all stages. The review protocol is registered with the PROSPERO database vide registration number CRD42013006496.

RESULTS

The pooled effect measure for the comparisons did not reveal an association in primary analyses. In the subgroup analyses, we observed a negative association between APOE4+ genotypes and overall risk of cancer in the cohort study subgroup (pooled OR 0.86; 95 % CI 0.82-0.91; p < 0.00001; I (2) = 0 %). Sensitivity analyses did not alter the overall pooled effect measure, and there were no evidences to suggest a publication bias.

CONCLUSION

Overall, the present meta-analysis did not show any association between APOE alleles and genotypes with incidence of cancer in general.

Increased microRNA-630 expression in gastric cancer is associated with poor overall survival

MicroRNAs are noncoding RNAs that regulate multiple cellular processes during cancer progression. Among various microRNAs, MiR-630 has recently been identified to be implicated in many critical processes in human malignancies. We aimed to investigate the significance and prognostic value of miR-630 in human gastric cancer. Gastric cancer and adjacent normal specimens from 236 patients from who had not received neoadjuvant chemotherapy were collected. The expression of miR-630 was investigated by quantitative real-time PCR assay and its association with overall survival of patients was analyzed by statistical analysis. MiR-630 expression level was significantly elevated in gastric cancer in comparison to adjacent normal specimens. It is also proved that miR-630 expression was to be associated with gastric cancer invasion, lymph node metastasis, distant metastasis and TNM stage. In addition, survival analysis proved that elevated miR-630 expression was associated with poor overall survival of patients. Multivariate survival analysis also proved that miR-630 was an independent prognostic marker after adjusted for known prognostic factors. The present study proved the over-expression of miR-630 and its association with tumor progression in human gastric cancer. It also provided the first evidence that miR-630 expression was an independent prognostic factor for patients with gastric cancer, which might be a potential valuable biomarker for gastric cancer.

Role of 3’-untranslated region translational control in cancer development, diagnostics and treatment

The messenger RNA 3’-untranslated region (3’UTR) plays an important role in regulation of gene expression on the posttranscriptional level. The 3’UTR controls gene expression via orchestrated interaction between the structural components of mRNAs (cis-element) and the specific trans-acting factors (RNA binding proteins and non-coding RNAs). The crosstalk of these factors is based on the binding sequences and/or direct protein-protein interaction, or just functional interaction. Much new evidence that has accumulated supports the idea that several RNA binding factors can bind to common mRNA targets: to the non-overlapping binding sites or to common sites in a competitive fashion. Various factors capable of binding to the same RNA can cooperate or be antagonistic in their actions. The outcome of the collective function of all factors bound to the same mRNA 3’UTR depends on many circumstances, such as their expression levels, affinity to the binding sites, and localization in the cell, which can be controlled by various physiological conditions. Moreover, the functional and/or physical interactions of the factors binding to 3’UTR can change the character of their actions. These interactions vary during the cell cycle and in response to changing physiological conditions. Abnormal functioning of the factors can lead to disease. In this review we will discuss how alterations of these factors or their interaction can affect cancer development and promote or enhance the malignant phenotype of cancer cells. Understanding these alterations and their impact on 3’UTR-directed posttranscriptional gene regulation will uncover promising new targets for therapeutic intervention and diagnostics. We will also discuss emerging new tools in cancer diagnostics and therapy based on 3’UTR binding factors and approaches to improve them.

A functional polymorphism in the promoter region of microRNA-146a is associated with the risk of Alzheimer disease and the rate of cognitive decline in patients

miR146a is well known for its regulatory role in the immune response and inflammation. Recent studies have demonstrated the links between miR146a and Alzheimer disease (AD) and suggested that miR146a may be involved in neuroinflammation and the metabolism of amyloid-β (Aβ), which are critical events in AD pathology. Although genetic studies have focused on the association between the miR146a gene and susceptibility to several diseases, no association study of miR146a variability with AD has been conducted. In this report, we performed a case-control association study to analyze the genotype and allele distributions of the miR146a, rs2910464 and rs57095329 polymorphisms in a Chinese population consisting of 292 AD cases and 300 healthy controls. We found a significant difference in the genotypes and allele frequencies of rs57095329 between the AD cases and the controls (p = 0.0147 and p = 0.0184, respectively), where the AA genotype of rs57095329 was associated with an increased risk of AD as well the cognitive decline in AD patients. Additionally, the AA genotype of rs57095329 exhibited significantly higher miR146a expression than the GG+GA genotypes of rs2910164 in the peripheral blood cells (PBMCs) of healthy individuals and had a stronger effect on the production of IL-6 and IL-1β when the cells were stimulated with LPS. Our data provide preliminary evidence that the rs57095329 polymorphism in the miR146a promoter is involved in the genetic susceptibility to AD, and this risk AA genotype may increase the expression of miR146a and influence certain proinflammatory cytokines, thus playing a role in the pathogenesis of AD.

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.

Effects of common polymorphisms rs2910164 in miR-146a and rs11614913 in miR-196a2 on susceptibility to colorectal cancer: a systematic review meta-analysis

PURPOSE

Emerging evidence has shown that single nucleotide polymorphisms occurred in microRNAs may contribute to the development of colorectal cancer (CRC). rs2910164 in miR-146a and rs11614913 in miR-196a2 are suggested to be associated with the susceptibility to CRC, but individually published studies revealed inconclusive results. To systematically summarize the possible correlationship between these polymorphisms and CRC risk, we performed this meta-analysis.

METHODS

We retrieved the relevant articles of the associations between these two microRNA polymorphisms and susceptibility to CRC for the period up to July 1, 2013. A total of seven articles were identified with 2,143 cases and 2,457 controls for miR-146a rs2910164, 1,594 cases and 2,252 controls for miR-196a2 rs11614913. Odds ratio and 95 % confidence interval were calculated to investigate the strength of the association.

RESULTS

The pooled analysis showed that miR-146a rs2910164 did not reveal any correlation with CRC susceptibility. However, a decreased risk was observed between miR-196a2 rs11614913 and CRC in all genetic models.

CONCLUSION

Our current meta-analysis demonstrates that miR-196a2 rs11614913 most likely contributes to decreased risk of CRC, whereas miR-146a rs2910164 may not be associated with the susceptibility to CRC.

Positive association between miR-499A>G and hepatocellular carcinoma risk in a Chinese population

A case-control study of the association of miR-499A>G rs3746444 with risk of hepatocellular carcinoma (HCC)was conducted. Patients with HCC and healthy control subjects were recruited for genotyping of miR- 499A>G using duplex polymerase-chain-reaction with confronting-two-pair primer(PCR-RFLP) analysis. The MiR-499 GG genotype was associated with a decreased risk of HCC as compared with the miR-499 AA genotype (adjusted OR=0.74, 95%CI=0.24-0.96). Similarly, the GG genotype showed a 0.45-fold decreased HCC risk in a recessive model. The MiR-499 G allele was significantly associated with decreased risk of HCC among patients infected with HBV in a dominant model (OR=0.09, 95%CI= 0.02-0.29). In conclusion, the MiR-499A>G rs3746444 polymorphism is associated with HCC risk in the Chinese population, and may be useful predictive marker for CAD susceptibility.

Hsa-miR-196a2 polymorphism increases the risk of acute lymphoblastic leukemia in Chinese children

Acute lymphoblastic leukemia (ALL) is a major cause of mortality and morbidity in childhood, and the causes of ALL are not completely understood. microRNAs (miRNAs) regulate various biological processes including organ development, cell growth regulation, cell differentiation, apoptosis, and tumorigenesis. We performed a case-control study with 570 childhood ALL cases and 673 cancer-free controls to investigate the association between hsa-miR-196a2 rs11614913 T>C polymorphism and ALL risk. The bioinformatics was used to estimate the potential target of hsa-miR-196a2. In the present study, the hsa-miR-196a2 variant TC heterozygote, and CC/TC genotypes were found to be associated with a significantly increased childhood ALL risk, compared with the TT wild-type homozygote (adjusted OR=1.50, 95% CI=1.15-1.95 for TC and OR=1.40, 95% CI=1.09-1.79 for CC/TC). Further, the difference was pronounced in younger (≤6) subjects or parental non-drinker. The significance of the increased risk is more obvious than the higher treatment branch. Additionally, we found that the rs11614913 TC genotype can increase B-phenotype ALL risk (OR=1.37, 95% CI=1.07-1.76). Finally, combination of three bioinformatics approaches revealed that HOXC8 may be the target gene of hsa-miR-196a2. Taken together, our finding suggested that hsa-miR-196a2 rs11614913 T>C may increase the risk of childhood ALL. Large studies with the function of hsa-miR-196a2 are needed in the further study.

Association between microRNA polymorphisms and cancer risk based on the findings of 66 case-control studies

MicroRNAs (miRNAs) are small non-coding RNA molecules, which participate in diverse biological processes and may regulate tumor suppressor genes or oncogenes. Single nucleotide polymorphisms (SNPs) in miRNA may contribute to diverse functional consequences, including cancer development, by altering miRNA expression. Numerous studies have shown the association between miRNA SNPs and cancer risk; however, the results are generally debatable and inconclusive, mainly due to limited statistical power. To assess the relationship between the five most common SNPs (miR-146a rs2910164, miR-196a2 rs11614913, miR-499 rs3746444, miR-149 rs2292832, and miR-27a rs895919) and the risk cancer development, we performed a meta-analysis of 66 published case-control studies. Crude odds ratios at 95% confidence intervals were used to investigate the strength of the association. No association was observed between rs2910164 and cancer risk in the overall group. However, in stratified analysis, we found that either the rs2910164 C allele or the CC genotype was protective against bladder cancer, prostate cancer, cervical cancer, and colorectal cancer, whereas it was a risk factor for papillary thyroid carcinoma and squamous cell carcinoma of the head and neck (SCCHN). Further, rs11614913 was found to be significantly associated with decreased cancer risk, in particular, for bladder cancer, gastric cancer, and SCCHN. For miR-499, a significant association was found between the rs3746444 polymorphism and cancer risk in pooled analysis. In subgroup analysis, similar results were mainly observed for breast cancer. Finally, no association was found between rs2292832 and rs895919 polymorphisms and cancer risk in the overall group and in stratified analysis. In summary, miR-196a2 rs11614913, miR-146a rs2910164, and miR-499 rs3746444 are risk factors for cancer development, whereas mir-149 rs2292832 and miR-27a rs895919 are not associated with cancer risk.

A functional variant of pre-miRNA-196a2 confers risk for Behcet's disease but not for Vogt-Koyanagi-Harada syndrome or AAU in ankylosing spondylitis

This study aimed to investigate the predisposition of common pre-miRNA SNPs with Behcet's disease (BD), Vogt-Koyanagi-Harada (VKH) syndrome and acute anterior uveitis (AAU) associated with ankylosing spondylitis (AS). A two-stage association study was carried out in 859 BD, 400 VKH syndrome, 209 AAU(+)AS(+) patients and 1,685 controls all belonging to a Chinese Han population. Genotyping, the expression of miR-196a and Bach1 (the target gene of miR-196a), cell proliferation, cytokine production were examined by PCR-RFLP, real-time PCR, CCK8 and ELISA. In the first stage study, the results showed significantly increased frequencies of the miR-196a2/rs11614913 TT genotype and T allele in BD patients (adjusted P(c) = 0.024, OR = 1.63; adjusted P(c) = 5.4 × 10(-3), OR = 1.45, respectively). However, no significant association of the tested SNPs with VKH and AAU(+)AS(+) patients was observed. The second stage and combined studies confirmed the association of rs11614913 with BD (TT genotype: adjusted P(c) = 6×10(-5), OR = 1.53; T allele: adjusted P(c) = 8×10(-6), OR = 1.35; CC genotype: adjusted P(c) = 0.024, OR = 0.68). A stratified analysis showed an association of the rs11614913 TT genotype and T allele with the arthritis subgroup of BD (P(c) = 5.3 × 10(-3), OR = 1.89; P(c) = 0.015, OR = 1.56, respectively). Functional experiments showed a decreased miR-196a expression, an increased Bach1 expression and an increased production of IL-1β and MCP-1 in TT cases compared to CC cases (P = 0.023, P = 0.0073, P = 0.012, P = 0.002, respectively). This study shows that a functional variant of miR-196a2 confers risk for BD but not for VKH syndrome or AAU(+)AS(+) by modulating the miR-196a gene expression and by regulating pro-inflammatory IL-1β and MCP-1 production.

MiR-196a2 rs11614913 T > C polymorphism and risk of esophageal cancer in a Chinese population

BACKGROUND

Esophageal cancer is the eighth most common cancer and sixth leading cause of cancer associated death worldwide. Besides environmental risk factors, genetic factors might play an important role in the esophageal cancer carcinogenesis.

METHODS

We conducted a hospital based case-control study to evaluate the genetic susceptibility of functional single nucleotide polymorphisms (SNPs) in the microRNAs on the development of esophageal cancer. A total of 380 esophageal squamous cell carcinoma (ESCC) cases and 380 controls were recruited for this study. The miR-196a2 rs11614913 T > C, miR-146a rs2910164 C > G, miR-499 rs3746444 T > C, miR-26a-1 rs7372209 C > T and miR-27a rs895819 T > C genotypes were determined using a custom-by-design 48-Plex SNPscan™ Kit and matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).

RESULTS

MiR-196a2 rs11614913 T > C polymorphism was associated with borderline statistically decreased risk of ESCC. In the recessive model, when the miR-196a2 rs11614913 TT/TC genotypes were used as the reference group, the CC homozygote genotype was associated with a borderline statistically decreased risk for ESCC (adjusted OR 0.72, 95% CI 0.50-1.03, p = 0.070). In stratification analyses, a significantly decreased risk of ESCC associated with the miR-196a2 rs11614913 T > C polymorphism was evident among women patients and patients who never smoking or drinking.

CONCLUSIONS

These findings indicated that functional polymorphism miR-196a2 rs11614913 T > C might contribute to decreased ESCC risk among women patients and patients who never smoking or drinking. However, our results were obtained with a limited sample size. Future larger studies with other ethnic populations and tissue-specific biological characterization are required to confirm current findings.