A genetic variant in pre-miR-27a is associated with a reduced breast cancer risk in younger Chinese population

The diagnostic and prognostic role of miR-27a in cancer

MicroRNA-27a (miR-27a) has been reported to be abnormally expressed in patients with cancer, and it could play potential roles as a diagnostic and prognostic biomarker of cancers. However, the diagnostic and prognostic role remains unclear. Hence, this meta-analysis, based on published data, was conducted to assess the utility of miR-27a as a diagnostic and prognostic marker in various cancers. To identify eligible studies, databases: Web of Science, PubMed, and CNKI were searched, with 868 literatures obtained, 16 of which were included in the Meta-analysis. The pooled results of studies conducted with serum/plasma showed that miR-27a was a valuable diagnostic biomarker in cancers (area under curve (AUC)= 0.91, sensitivity (SEN)= 0.84, specificity (SPE)= 0.85), with the diagnostic value slightly reduced in tumor tissue samples (AUC=0.83, SEN=0.78, SPE: 0.74). Additionally, the pooled results revealed that high expression of miR-27a predicted poor prognosis of cancer in serum/plasma (hazard ratio (HR) = 0.63, P_{Heterogeneity} = 0.278, I²= 21.50%) but not in tumor tissue (HR = 0.98, P_{Heterogeneity} =0.577, I²= 0.0). In brief, our results suggested that miR-27a in serum/plasma or tumor tissue could act as a diagnostic biomarker, and that miR-27a in serum/plasma could predict cancer patients' survival.

Potential Impact of PI3K-AKT Signaling Pathway Genes, KLF-14, MDM4, miRNAs 27a, miRNA-196a Genetic Alterations in the Predisposition and Progression of Breast Cancer Patients

Genome-wide association studies have reported link between SNPs and risk of breast cancer. This study investigated the association of the selected gene variants by predicting them as possible target genes. Molecular technique advances with the availability of whole-exome sequencing (WES), now offer opportunities for simultaneous investigations of many genes. The experimental protocol for PI3K, AKT-1, KLF-14, MDM4, miRNAs 27a, and miR-196a genotyping was done by ARMS-PCR and sanger sequencing. The novel and known gene variants were studied by Whole-exome sequencing using Illumina NovaSeq 6000 platform. This case control study reports significant association between BC patients, healthy controls with the polymorphic variants of PI3K C > T, AKT-1 G > A KLF 14 C > T, MDM4 A > G, miR-27a A > G, miR-196a-2 C > T genes (p < 0.05). MDM4 A > G genotypes were strongly associated with BC predisposition with OR 2.08 & 2.15, p < 0.05) in codominant and dominant models respectively. MDM4 A allele show the same effective (OR1.76, p < 0.05) whereas it remains protective in recessive model for BC risk. AKT1G > A genotypes were strongly associated with the BC susceptibility in all genetic models whereas PI3K C > T genotypes were associated with breast cancer predisposition in recessive model OR 6.96. Polymorphic variants of KLF-14 A > G, MDM4G > A, MiR-27aA >G, miR-196a-C > T were strongly associated with stage, tamoxifen treatment. Risk variants have been reported by whole exome sequencing in our BC patients. It was concluded that a strong association between the PI3K-AKT signaling pathway gene variants with the breast cancer susceptibility and progression. Similarly, KLF 14-AA, MDM4-GA, miR27a-GG and miR-196a-CT gene variants were associated with the higher risk probability of BC and were strongly correlated with staging of the BC patients. This study also reported Low, novel, and intermediate-genetic-risk variants of PI3K, AKT-1, MDM4G & KLF-14 by utilizing whole-exome sequencing. These variants should be further investigated in larger cohorts' studies.

Predicting multiple types of miRNA-disease associations using adaptive weighted nonnegative tensor factorization with self-paced learning and hypergraph regularization

More and more evidence indicates that the dysregulations of microRNAs (miRNAs) lead to diseases through various kinds of underlying mechanisms. Identifying the multiple types of disease-related miRNAs plays an important role in studying the molecular mechanism of miRNAs in diseases. Moreover, compared with traditional biological experiments, computational models are time-saving and cost-minimized. However, most tensor-based computational models still face three main challenges: (i) easy to fall into bad local minima; (ii) preservation of high-order relations; (iii) false-negative samples. To this end, we propose a novel tensor completion framework integrating self-paced learning, hypergraph regularization and adaptive weight tensor into nonnegative tensor factorization, called SPLDHyperAWNTF, for the discovery of potential multiple types of miRNA-disease associations. We first combine self-paced learning with nonnegative tensor factorization to effectively alleviate the model from falling into bad local minima. Then, hypergraphs for miRNAs and diseases are constructed, and hypergraph regularization is used to preserve the high-order complex relations of these hypergraphs. Finally, we innovatively introduce adaptive weight tensor, which can effectively alleviate the impact of false-negative samples on the prediction performance. The average results of 5-fold and 10-fold cross-validation on four datasets show that SPLDHyperAWNTF can achieve better prediction performance than baseline models in terms of Top-1 precision, Top-1 recall and Top-1 F1. Furthermore, we implement case studies to further evaluate the accuracy of SPLDHyperAWNTF. As a result, 98 (MDAv2.0) and 98 (MDAv2.0-2) of top-100 are confirmed by HMDDv3.2 dataset. Moreover, the results of enrichment analysis illustrate that unconfirmed potential associations have biological significance.

Exploration of shared TF-miRNA‒mRNA and mRNA-RBP-pseudogene networks in type 2 diabetes mellitus and breast cancer

Type 2 diabetes mellitus (T2DM) has been confirmed to be closely associated with breast cancer (BC). However, the shared mechanisms between these diseases remain unclear. By comparing different datasets, we identified shared differentially expressed (DE) RNAs in T2DM and BC, including 427 mRNAs and 6 miRNAs from the GEO(Gene Expression Omnibus) database. We used databases to predict interactions to construct two critical networks. The transcription factor (TF)-miRNA‒mRNA network contained 236 TFs, while the RNA binding protein (RBP)-pseudogene-mRNA network showed that the pseudogene S-phase kinase associated protein 1 pseudogene 1 (SKP1P1) might play a key role in regulating gene expression. The shared mRNAs between T2DM and BC were enriched in cytochrome (CYP) pathways, and further analysis of CPEB1 and COLEC12 expression in cell lines, single cells and other cancers showed that they were strongly correlated with the survival and prognosis of patients with BC. This result suggested that patients with T2DM presenting the downregulation of CPEB1 and COLEC12 might have a higher risk of developing BC. Overall, our work revealed that high expression of CYPs in patients with T2DM might be a susceptibility factor for BC and identified novel gene candidates and immune features that are promising targets for immunotherapy in patients with BC.

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.

Association between miR-27a rs895819 polymorphism and breast cancer susceptibility: Evidence based on 6118 cases and 7042 controls

BACKGROUND

Polymorphism in miR-27a rs895819 has been associated with breast cancer (BC) risk, but studies have reported inconsistent results. This meta-analysis investigated the possible association between miR-27a rs895819 polymorphism and BC risk.

METHODS

PubMed, EMBASE, Google Scholar, and the Chinese National Knowledge Infrastructure (CNKI) databases were systematically searched to identify relevant studies in English and Chinese. Meta-analyses were performed to examine the association between miR-27a rs895819 and BC susceptibility.

RESULTS

A total of 16 case-control studies involving 6118 cases and 7042 controls were included. Analysis using five genetic models suggested no significant association between miR-27a rs895819 polymorphism and BC risk in the total population, or specifically in Asian or Chinese subpopulations. In the Caucasian subpopulation, however, the G-allele and AG genotype at rs895819 were significantly associated with decreased BC risk according to the allelic model (OR 0.90, 95% CI 0.84-0.97, P = .004) and heterozygous model (OR 0.89, 95% CI 0.81-089, P = .02), while the wild-type AA genotype was significantly associated with increased BC risk according to the dominant model (OR 1.13, 95% CI 1.03-1.24, P = .007).

CONCLUSION

These results indicate that among Caucasians, the wild-type AA genotype at rs895819 may confer increased susceptibility to BC, while the G-allele and AG genotype may be protective factors. These conclusions should be verified in large, well-designed studies.

Associations of genetic variants of miRNA coding regions with pulmonary tuberculosis risk in China

Tuberculosis (TB) is the leading cause of death caused by single pathogenic microorganism, Mycobacterium tuberculosis (MTB). The study aims to explore the associations of microRNA (miRNA) single-nucleotide polymorphisms (SNPs) with pulmonary TB (PTB) risk. A population-based case−control study was conducted, and 168 newly diagnosed smear-positive PTB cases and 251 non-TB controls were recruited. SNPs located within miR-27a (rs895819), miR-423 (rs6505162), miR-196a-2 (rs11614913), miR-146a (rs2910164), miR-618 (rs2682818) were selected and MassARRAY^® MALDI-TOF System was employed for genotyping. SPSS19.0 was adopted for statistical analysis, non-conditional logistic regression was performed. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were computed to estimate the associations. Associations of haplotypes with PTB risk were performed with online tool. Rs895819 CT/CC genotype was associated with reduced PTB risk among female population (OR = 0.45, 95% CI: 0.23–0.98), P = 0.045. Haplotypes (combined with rs895819, rs2682818, rs2910164, rs6505162 and rs11614913) TCCCT, TAGCC, CCCCC, CCGCT and TCGAT were associated with reduced PTB risk and the ORs were 0.67 (95% CI: 0.45–0.99), 0.49 (0.25–0.94), 0.34 (95% CI: 0.14–0.81), 0.22 (95% CI: 0.06–0.84) and 0.24 (95% CI: 0.07–0.79), respectively; while the haplotypes of TAGCT, CCCCT, CACCT and TCCAT were associated with increased PTB risk, and the ORs were 3.63 (95% CI: 1.54–8.55), 2.20 (95% CI: 1.00–4.86), 3.90 (95% CI: 1.47–10.36) and 2.95 (95% CI: 1.09–7.99), respectively. Rs895819 CT/CC genotype was associated with reduced female PTB risk and haplotype TCCCT, TAGCC, CCCCC, CCGCT and TCGAT were associated with reduced PTB risk, while TAGCT, CCCCT, CACCT and TCCAT were associated with increased 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.

hsa-miR-423 rs6505162 Is Associated with The Increased Risk of Breast Cancer in Isfahan Central Province of Iran

Objective

Thirteen million cancer deaths and 21.7 million new cancer cases are expected in the world by 2030. Breast cancer is considered as the main cause of cancer mortality in women aged 20-59 years. microRNAs (miRNAs) regulate gene expression at the post-transcriptional level and they are highly expressed in malignancies, including breast cancer. The role of miRNAs in the pathogenesis of breast cancer is not fully understood. In the present study, for the first time, the impact of hsa-miR-423 rs6505162 on breast cancer risk was investigated in the central province of Iran, Isfahan.

Materials and Methods

This case-control study was conducted on 153 clinicopathological proven breast cancer patients and 153 sex-matched healthy women with no history of any cancer type and relative patients. The patients and controls were genotyped and association of their clinical characteristics with hsa-miR-423 rs6505162 genotype was analyzed.

Results

The findings indicated that CC genotype of hsa-miR-423 rs6505162 was associated with the increased risk of breast cancer [odds ratio (OR)=2.37, 95% confidence interval (CI)=1.29-4.35 and P=0.0023, CC vs. AA].

Conclusion

The data suggested that hsa-miR-423 rs6505162 could be considered as a novel risk factor in breast cancer pathogenesis in Isfahan province of Iran.

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Pre-miR-27a rs895819 polymorphism and risk of diffuse large B-cell lymphoma

Background

Recently, several studies have investigated the relationship between Pre‐miR‐27a rs895819 polymorphism and risk of various cancers. However, the relationship between rs895819 and diffuse large B‐cell lymphoma (DLBCL) has not been well known.

Methods

In this study, we conducted a case‐control study to explore the role of Pre‐miR‐27a rs895819 in risk of DLBCL. The PCR‐TaqMan and luciferase assays and in vitro experiments were used to evaluate polymorphism function.

Results

As a result, we found subjects carrying with rs895819 AG/GG genotype had a significantly decreased risk when compared with those carrying the AA genotype. Further qPCR assay showed that the DLBCL patients carrying AG/GG genotypes showed a lower level of mature miR‐27a when compared with patients carrying AA genotype. Moreover, miR‐27a levels were upregulated in DLBCL tissues compared with normal lymphoid tissues. Further in vitro experiments showed that miR‐27a might function as an oncogene through target TGFBR1. In addition, TGFBR1 overexpression rescues effects of miR‐27a inhibitor on DLBCL cells phenotypes.

Conclusions

In conclusion, these findings indicate that rs895819 A > G might reduce the expression of mature miR‐27a, and leading a higher level of TGFBR1, ultimately inhibiting the development of DLBCL.

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.

MiR-27a: A Novel Biomarker and Potential Therapeutic Target in Tumors

MicroRNAs (miRNAs) are endogenous, time sequencing, conserved and small non-coding RNA molecules (19-25 bp long) that regulate gene expression at the post-transcriptional level by binding to the partial sequence homology of the 3'-untranslated region of target messenger (m)RNA. The miRNA-27 family consists of miR-27a and miR-27b, which are transcribed from different chromosomes and different in nucleotide at the 3' end. It has been reported that miR-27a was located on chromosome 19 and played a vital role in tumor development. Increasing evidences support a vital role for miR-27a in modulating polymorphisms, tumorigenesis, proliferation, apoptosis, invasion, migration and angiogenesis. Apart from it, miR-27a could affect drug sensitivity, treatment of cancer and patients prognosis. The miR-27a could be an oncogene or a tumor suppressor in several types of cancer, including colon cancer, pancreatic cancer, breast cancer, bladder cancer and hepatocellular carcinoma. In this review, we discuss the role of miR-27a in tumor biology and clinical significance in detail and offer novel insights into molecular targeting therapy for human cancers.

Breast Cancer and miR-SNPs: The Importance of miR Germ-Line Genetics

Recent studies in cancer diagnostics have identified microRNAs (miRNAs) as promising cancer biomarkers. Single nucleotide polymorphisms (SNPs) in miRNA binding sites, seed regions, and coding sequences can help predict breast cancer risk, aggressiveness, response to stimuli, and prognosis. This review also documents significant known miR-SNPs in miRNA biogenesis genes and their effects on gene regulation in breast cancer, taking into account the genetic background and ethnicity of the sampled populations. When applicable, miR-SNPs are evaluated in the context of other patient factors, including mutations, hormonal status, and demographics. Given the power of miR-SNPs to predict patient cancer risk, prognosis, and outcomes, further study of miR-SNPs is warranted to improve efforts towards personalized medicine.

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

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

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

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

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

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

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

Association 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.

The association between differentially expressed micro RNAs in breast cancer cell lines and the micro RNA-205 gene polymorphism in breast cancer tissue

Micro (mi)RNAs are an endogenous non-coding small RNA comprised of 19–26 nucleotides. miRNAs regulate gene expression through the recognition of its ‘seed sequence’ and interactions with 3′-untranslated region of target miRNAs. Previous studies identified that miRNAs are associated with the onset and development of breast cancer and that a number of mutations in the coding DNA sequence of miRNAs affect its expression. Therefore, the present study aimed to screen differentially expressed miRNAs using miRNA expression profile chips to analyze the expression of miRNA (miR)-205 in 12 breast cell lines of different metastatic performance and benign proliferative variation as well as breast cancer via in-situ hybridization, and screen out single-nucleotide polymorphisms (SNPs) in the miR-205 coding gene region. In addition, the association between SNP and the clinicopathological features of breast lesions was investigated. The results of the present study demonstrated that the expression of miR-205 was decreased in breast cancer cells and tissues compared with benign lesions. SNPs in the miR-205 coding gene region were identified in tumor cell lines and as increasing lengths of the AGC repetitive sequence were lost, miR-205 expression increased. An association was identified between a number of SNPs in the miR-205 coding gene region and breast cancer, as well as between SNPs in miR-205 coding gene region and the clinicopathological features of breast cancer.

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

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

Genetic polymorphisms in pre-miRNAs predict the survival of non-small-cell lung cancer in Chinese population: a cohort study and a meta-analysis

BACKGROUND

To explore the association of genetic polymorphisms in pre-miRNA 30c-1 rs928508 and pre-miRNA 27a rs895819 with non-small-cell lung cancer prognosis.

MATERIALS AND METHODS

480 patients from five hospitals were enrolled in this prospective cohort study. They were followed up for five years. The association between genotypes and overall survival was assessed by Cox proportional hazards regression models. A meta-analysis was conducted to provide evidence for the effect of microRNA 27a rs895819 on cancer survival.

RESULTS

G-allele containing genotypes of microRNA 30c-1 polymorphisms and C-allele containing genotypes of microRNA 27a were significantly associated with poorer overall survival. Multivariate Cox regression models indicated that these genetic polymorhpisms were independently predictive factors of poorer overall survival. In stratified analysis, the effect was observed in many strata. The significant joint effect was also observed in our study. Patients with G allele of microRNA 30c-1 rs928508 and C allele of microRNA 27a rs895819 had the poorer overall survival than patients with C allele of rs928508 and T allele of rs895819. The effect of the microRNA 27a rs895819 on non-small cell lung cancer overall survival was supported by the meta-analysis results.

CONCLUSIONS

The two single nucleotide polymorphisms in microRNA 30c-1 and microRNA 27a can predict the outcome of non-small cell lung cancer patients and they may decrease the sensitivity to anti-cancer drugs.

Distinct effects of rs895819 on risk of different cancers: an update meta-analysis

Previous studies have indicated an association between the genetic variant in pre-miR-27a rs895819 with A->G transition and cancer risk; however, the results remain inconsistent and somehow conflicting in different cancers. Therefore, to obtain a more reliable conclusion, we performed an update meta-analysis by searching PubMed database or other databases. Odds ratio (ORs) and 95% confidence interval (CIs) were calculated to evaluate cancer risk. A total of 34 case-control studies involving 15,388 cases and 18,704 controls were included. The results showed that rs895819 was associated with an increased cancer risk (GG vs. AA/AG: OR = 1.15, 95% CI = 1.02-1.29). Furthermore, stratification analyses revealed an association of rs895819 with increased cancer risk among Asians (GG vs. AA: OR = 1.17, 95% CI = 1.01-1.36; GG vs. AA/AG: OR = 1.18, 95% CI = 1.03-1.35), but not Caucasians. Interestingly, the [G] allele of rs895819 was significantly associated with decreased risk of breast cancer (G vs. A: OR = 0.91, 95% CI = 0.86-0.97). However, rs895819 was associated with increased risk of colorectal cancer (GG vs. AA: OR = 1.56, 95% CI = 1.31-1.85; GG vs. AA/AG: OR = 1.53, 95% CI = 1.30-1.79; G vs. A: OR = 1.19, 95% CI = 1.09-1.30) and lung cancer (GG vs. AA/AG: OR = 1.43, 95% CI = 1.00-2.04). In addition, no association was found between rs895819 and risk of gastric cancer or esophageal cancer. In conclusion, our findings suggest distinct effects of rs895819 on risk of different cancers, and future well-designed studies with large samples are required to further validate our results.

MiR-27a rs895819 is involved in increased atrophic gastritis risk, improved gastric cancer prognosis and negative interaction with Helicobacter pylori

MiR-27a rs895819 is a loop-stem structure single nucleotide polymorphism affecting mature miR-27a function. In this study, we performed a comprehensive analysis about the association of rs895819 with gastric cancer risk and prognosis, atrophic gastritis risk, as well as the interactions with environmental factors. A total of 939 gastric cancer patients, 1,067 atrophic gastritis patients and 1,166 healthy controls were screened by direct sequencing and MALDI-TOF-MS. The association of rs895819 with clinical pathological parameters and prognostic survival in 357 gastric cancer patients was also been analyzed. The rs895819 variant genotype increased the risk for atrophic gastritis (1.58-fold) and gastric cancer (1.24-fold). While in stratified analysis, the risk effect was demonstrated more significantly in the female, age >60y, Helicobacter pylori (H. pylori) negative and non-drinker subgroups. Rs895819 and H. pylori showed an interaction effect for atrophic gastritis risk. In the survival analysis, the rs895819 AG heterozygosis was associated with better survival than the AA wild-type in the TNM stage I–II subgroup. In vitro study by overexpressing miR-27a, cells carrying polymorphic-type G allele expressed lower miR-27a than wild-type A allele. In conclusion, miR-27a rs895819 is implicated as a biomarker for gastric cancer and atrophic gastritis risk, and interacts with H. pylori in gastric carcinogenesis.

Effect of miRNA-27a and Leptin Polymorphisms on Risk of Recurrent Spontaneous Abortion

Background

The aim of this study was to investigate the possible associations of miRNA-27a and Leptin polymorphisms with the risk of recurrent spontaneous abortion (RSA).

Material/Methods

Between May 2013 and April 2015 at Shenzhen Longhua New District Central Hospital, we randomly recruited 138 RSA patients as the case group and another 142 normal pregnancy women as the control group. We used denaturing high-performance liquid chromatography (DHPLC) to determine the genotypes and allele frequencies of miRNA-27a rs895819 A/G and Leptin rs7799039 G/A.

Results

The GG genotype and G allele frequencies of miRNA-27a rs895819 A/G were higher in the case group than in the control group, and the AA genotype and A allele frequencies of Leptin rs7799039 G/A were also higher in the case group than in the control group (all P<0.05). MiRNA-27a rs895819 A/G and Leptin rs7799039 G/A polymorphisms increased the risk of RSA (Exp (B)=2.732, 95% CI=1.625~4.596, P=0.000; Exp (B)=4.081, 95% CI=1.817~9.164, P=0.001). GG-AA or AG-AA carriers had a higher risk of RSA. The miRNA-27a expression of AA carriers of miRNA-27a rs895819 was lower than that of AG+GG carriers both in the case and control groups (all P=0.024). The plasma leptin concentration of GG carriers was lower than that of GA+AA carriers in the case group (P=0.026).

Conclusions

The polymorphisms of miRNA-27a rs895819 A/G and Leptin rs7799039 G/A may contribute to an increased risk of RSA.

Effect of pre-miRNA-1658 gene polymorphism on chicken growth and carcass traits

Objective

Polymorphisms occurring in the precursor region of microRNAs (miRNAs) affect the target gene and alter the biogenesis of miRNAs, resulting in phenotypic variation. The purpose of the study was to investigate the genetic effects of rs16681031 (C>G) mutation in the precursor region of gga-miR-1658 on the economic traits of the Gushi-Anka chicken F2 resource population.

Methods

To explore the effect of miR-1658 polymorphisms on chicken economic traits, the SNP was genotyped by MassArray matrix-assisted laser desorption/ionization-time of flight mass spectrometry. The association between the SNP and chicken body size, growth and carcass traits was determined by linear mixed models.

Results

The SNP was not only significantly associated with body weight at the age of 6, 8, 10, 12 weeks, respectively, but also with the breadth of the chicken chest, body slanting length and pelvic breadth at 4 weeks, chest depth at 8 weeks of age, and body slanting length at 12 weeks (p<0.05), respectively.

Conclusion

Our data serve as a useful resource for further analysis of miRNA function, and represent a molecular genetic basis for poultry breeding.

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.

In silico analysis of polymorphisms in microRNAs that target genes affecting aerobic glycolysis

BACKGROUND

Cancer cells preferentially metabolize glucose through aerobic glycolysis, an observation known as the Warburg effect. Recently, studies have deciphered the role of oncogenes and tumor suppressor genes in regulating the Warburg effect. Furthermore, mutations in glycolytic enzymes identified in various cancers highlight the importance of the Warburg effect at the molecular and cellular level. MicroRNAs (miRNAs) are non-coding RNAs that posttranscriptionally regulate gene expression and are dysregulated in the pathogenesis of various types of human cancers. Single nucleotide polymorphisms (SNPs) in miRNA genes may affect miRNA biogenesis, processing, function, and stability and provide additional complexity in the pathogenesis of cancer. Moreover, mutations in miRNA target sequences in target mRNAs can affect expression.

METHODS

In silico analysis and cataloguing polymorphisms in miRNA genes that target genes directly or indirectly controlling aerobic glycolysis was carried out using different publically available databases.

RESULTS

miRNA SNP2.0 database revealed several SNPs in miR-126 and miR-25 in the upstream and downstream pre-miRNA flanking regions respectively should be inserted after flanking regions and miR-504 and miR-451 had the fewest. These miRNAs target genes that control aerobic glycolysis indirectly. SNPs in premiRNA genes were found in miR-96, miR-155, miR-25 and miR34a by miRNASNP. Dragon database of polymorphic regulation of miRNA genes (dPORE-miRNA) database revealed several SNPs that modify transcription factor binding sites (TFBS) or creating new TFBS in promoter regions of selected miRNA genes as analyzed by dPORE-miRNA.

CONCLUSIONS

Our results raise the possibility that integration of SNP analysis in miRNA genes with studies of metabolic adaptations in cancer cells could provide greater understanding of oncogenic mechanisms.

miR-27a rs895819 polymorphism and risk of cancer in Chinese population: a meta-analysis

OBJECTIVE

Previous studies have evaluated the association between miR-27a rs895819 polymorphism and cancer risk in Chinese population, but the results were inconclusive. The present meta-analysis was conducted to clarify these controversies.

METHODS

A comprehensive search was conducted to identify all relevant case-control studies of miR-27a rs895819 polymorphism and cancer risk in Chinese participants. We calculated odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of any association.

RESULTS

A total of 12 case-control studies involving 2655 cases and 3106 controls were included. Overall, the results suggested that there was no significant association between miR-27a rs895819 polymorphism and cancer risk in Chinese population (OR = 1.14, 95%CI 0.86 to1.15, P = 0.85 for GG vs. AA). In the subgroup analysis by the source of controls, no significant association was found either among hospital-based group (OR = 1.16, 95%CI 0.78 to 1.73) or population-based group (OR = 1.06, 95%CI 0.74 to 1.35). However, when stratified by cancer types, we found a significant association between the polymorphism with colorectal cancer (OR = 1.56, 95%CI 1.01 to 2.40 for GG vs. AA).

CONCLUSION

miR-27a rs895819 polymorphism was associated with increased risk of colorectal cancer in Chinese population.

Critical analysis of the potential for microRNA biomarkers in breast cancer management

Breast cancer is a complex and heterogeneous disease. Signaling by estrogen receptor (ER), progesterone receptor (PR), and/or human EGF-like receptor 2 (HER2) is a main driver in the development and progression of a large majority of breast tumors. Molecular characterization of primary tumors has identified major subtypes that correlate with ER/PR/HER2 status, and also subgroup divisions that indicate other molecular and cellular features of the tumors. While some of these research findings have been incorporated into clinical practice, several challenges remain to improve breast cancer management and patient survival, for which the integration of novel biomarkers into current practice should be beneficial. microRNAs (miRNAs) are a class of short non-coding regulatory RNAs with an etiological contribution to breast carcinogenesis. miRNA-based diagnostic and therapeutic applications are rapidly emerging as novel potential approaches to manage and treat breast cancer. Rapid technological development enables specific and sensitive detection of individual miRNAs or the entire miRNome in tissues, blood, and other biological specimens from breast cancer patients. This review focuses on recent miRNA research and its potential to address unmet clinical needs and challenges. The four sections presented discuss miRNA findings in the context of the following clinical challenges: biomarkers for early detection; prognostic and predictive biomarkers for treatment decisions using targeted therapies against ER and HER2; diagnostic and prognostic biomarkers for subgrouping of triple-negative breast cancer, for which there are currently no targeted therapies; and biomarkers for monitoring and characterization of metastatic breast cancer. The review concludes with a critical analysis of the current state of miRNA breast cancer research and the need for further studies using large patient cohorts under well-controlled conditions before considering the clinical implementation of miRNA biomarkers.

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

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

microRNAs miR-27a and miR-27b directly regulate liver dihydropyrimidine dehydrogenase expression through two conserved binding sites

Dihydropyrimidine dehydrogenase (DPD, encoded by DPYD) is the rate-limiting enzyme in the uracil catabolic pathway and has a pivotal role in the pharmacokinetics of the commonly prescribed anticancer drug 5-fluorouracil (5-FU). Deficiency of DPD, whether due to inadequate expression or deleterious variants in DPYD, has been linked to severe toxic responses to 5-FU. Little is known about the mechanisms governing DPD expression in the liver. In this report, we show increased accumulation of RNA-induced silencing complex (RISC) proteins on DPYD mRNA in cells overexpressing the highly homologous microRNAs (miRNA) miR-27a and miR-27b. These miRNAs were shown to repress DPD expression through two conserved recognition sites in DPYD. The IC50 of 5-FU for HCT116 cells overexpressing miR-27a or miR-27b was 4.4 μmol/L (both), significantly lower than that for cells expressing a nontargeting (scramble) control miRNA (14.3 μmol/L; P = 3.3 × 10(-5) and P = 1.5 × 10(-7), respectively). Mouse liver DPD enzyme activity was inversely correlated with expression levels of miR-27a (R(2) = 0.49; P = 0.0012) and miR-27b (R(2) = 0.29; P = 0.022). A common variant in the hairpin loop region of hsa-mir-27a (rs895819) was also shown to be associated with elevated expression of the miR-27a in a panel of cell lines (P = 0.029) and in a transgenic overexpression model (P = 0.0011). Furthermore, rs895819 was associated with reduced DPD enzyme activity (P = 0.028) in a cohort of 40 healthy volunteers. Taken together, these results suggest that miR-27a and miR-27b expression may be pharmacologically relevant modulators of DPD enzyme function in the liver. Furthermore, our data suggest that rs895819 may be a potential risk allele for 5-FU sensitivity.