Different effects of three polymorphisms in MicroRNAs on cancer risk in Asian population: evidence from published literatures

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

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

The miR-196a SNP Rs11614913 but not the miR-499 rs37464444 SNP is a Risk Factor for Non-small Cell Lung Cancer in an Iranian Population

BACKGROUND

Globally, lung cancer represents a major cause of cancer-related deaths. The regulation of gene expression is modulated by small noncoding RNAs called miRNAs that can act as both tumor suppressors and oncogenes. The maturation, expression and binding to target mRNAs is affected by single nucleotide polymorphisms (SNPs) in miRNA genomic regions thereby contributing to cancer susceptibility. SNPs Rs11614913 in miR196a and Rs3746444 in miR-499 are implicated in the development of cancers such as non-small cell lung cancer (NSCLC) in non-Arabic subjects.

MATERIALS AND METHODS

A small cohort of 204 participants including 104 lung cancer patients and 100 non-cancer controls subjects were enrolled into the study. The allele frequencies were determined by Polymerase Chain Reaction- Restriction Fragment Length Polymorphism (PCR-RFLP) and their correlation with lung cancer risk was determined.

RESULTS

The miR-196a rs11614913 polymorphism increased the risk of NSCLC (CC vs. TT+TC: OR= 2.26, 95%CI= 1.28 - 3.98, P= 0.0046) in a dominant genetic model. No statistically significant association was found between the miR-499 rs37464444 polymorphism and NSCLC.

CONCLUSION

The rs11614913 polymorphism in miR-196a, but not the miR-499 rs37464444 polymorphism, increased the risk of NSCLC. Further studies with larger sample sizes in correlation with functional outcomes at the cellular level should be undertaken.

A genetic variant in microRNA-146a is associated with sporadic breast cancer in a Southern Brazilian Population

MicroRNAs (miRNAs) play an essential role in gene expression and affect the development of tumours, including breast cancer (BC). Polymorphisms in miRNA genes can affect the interaction of miRNAs with their target messenger RNA by interfering, creating or disrupting target sites. The single nucleotide polymorphism (SNP) rs2910164, located in the seed region of miR146a, was shown to be associated with BC among different populations. In the present study, we investigated whether rs2910164 is associated with BC in 326 patients and 411 controls from a Brazilian population of predominantly European ancestry. The presence of the allele rs2910164*C was associated with an increased risk of BC (OR=1.4, 95% CI=1.03-1.85, p = 0.03). We also analysed publicly available RNA-seq data to evaluate if miR146a is differentially expressed in different subtypes of BC. Genotyping was performed by polymerase chain reaction with sequence-specific primers (PCR-SSP). By leveraging public data from TCGA database, we analysed 461 patients and found that miR146a is significantly more expressed in BC than in non-tumor tissue (1.47 fold, p = 0.02) and is expressed to a greater degree in aggressive BC subtypes.

Investigation of the Association of miRNA-499, miRNA-146a, miRNA-196a2 Loci with Hepatocellular Carcinoma Risk: A Case-Control Study Involving 1507 Subjects

microRNAs' (miRNAs) loci may influence hepatocellular carcinoma (HCC) development. Many recent studies have assessed the relationship between miRNA-499, miRNA-146a, and miRNA-196a2 loci and HCC risk. However, the observed results are conflicting. A total of 584 HCC patients and 923 age- and sex-matched controls were recruited. The correlation of miRNA-499 rs3746444, miRNA-146a rs2910164, and miRNA-196a2 rs11614913 with HCC development was assessed. In the <53-year-old subgroup, a correlation of the rs2910164 locus with HCC risk was found (GG/CG vs. CC: adjusted p = 0.011, GG vs. CC: adjusted p = 0.021 and CG vs. CC: adjusted p = 0.027). The association between miRNA-146a rs2910164 and the risk of HCC was also found in the never smoking (GG/CG vs. CC: adjusted p = 0.011 and CG vs. CC: adjusted p = 0.018). Using false-positive report probability method and power value, we identified that miRNA-146a rs2910164 conferred a risk to HCC in the <53-year-old and never-smoking subgroups. In conclusion, this study indicates rs2910164 may be a risk factor for HCC, especially in the <53-year-old and never-smoking subgroups.

miRNA 196a2(rs11614913) & 146a(rs2910164) polymorphisms & breast cancer risk for women in an Iranian population

AIM

The purpose of our study was to analyze association of miRNAs 146aG/C(2910164) and 196a2C/T(11614913) polymorphism with breast cancer (BC) risk for women of Azeri ethnicity in Iran.

MATERIALS & METHODS

In the current case (n = 200)-control (n = 200) study, miRNAs 146aG/C(2910164) and 196a2C/T(11614913) were investigated for allelic and genotypic levels via the PCR-restriction fragment length polymorphism technique.

RESULTS

The statistical analysis showed a significant relation between CC genotype of rs11614913(196a2) (codominant, odds ratio (OR) = 0.58, p = 0.02236; recessive, OR = 2.92, p = 0.01695; overdominant, OR = 0.44, p = 0.0113) and BC susceptibility. The subgroup analysis of mentioned polymorphism declared the significant correlation (p ≤ 0.05) of the positive abortion, regular menstruation, positive human epidermal receptor-2 and positive estrogen receptor with BC susceptibility in CC genotype.

CONCLUSION

The existence of a C-allele at miRNA 196a2(11614913) elevates women's BC susceptibility in Azeri ethnicity in Iran.

Association of rs3787016 in Long Non-coding RNAs POLR2E and rs2910164 in MiRNA-146a with Prostate Cancer: A Systematic Review and Meta-analysis

BACKGROUND

The aim of this study was to conduct a meta-analysis to estimate the association between the two SNPs and PCa risk.

METHODS

Medline, Embase, Scopus, PubMed, Web of Science, Wan Fang Database and Chinese Zhi Wang Database were searched for the association of the two SNPs with susceptibility to PCa. The effect size was pooled by odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS

Nine case-control studies, 5 on rs3787016 and 4 on rs2910164, were included. As regards rs3787016, an increased risk of PCa was identified in all genotype models (T versus C: OR = 1.18, 95% CI 1.11-1.25; CT versus CC: OR = 1.17, 95% CI 1.08-1.26; TT versus CC: OR = 1.41, 95% CI 1.22-1.63; TT + CT versus CC: OR = 1.20, 95% CI 1.12-1.30; TT versus CT + CC: OR = 1.32, 95% CI 1.15-1.52). However, no significant association was found between rs2910164 and PCa risk in any genetic models, in fact a trend of reduced risk could be seen (C versus G: OR = 0.91, 95% CI 0.79-1.05; GC versus GG: OR = 0.93, 95% CI 0.74-1.18; CC versus GG: OR = 0.70, 95% CI 0.47-1.02; CC + GC versus GG: OR = 0.90, 95% CI 0.73-1.12; CC versus GC + GG: OR = 0.78, 95% CI 0.56-1.08). Besides, in analysis of subgroups by source of controls, the decreased results were observed in studies using population-based controls.

CONCLUSION

lncRNA POLR2E polymorphism rs3787016 is associated with a significantly increased risk of PCa, while a trend of reduced risk appears with mir-146a polymorphism rs2910164.

Genome-wide miRNA response to anacardic acid in breast cancer cells

MicroRNAs are biomarkers and potential therapeutic targets for breast cancer. Anacardic acid (AnAc) is a dietary phenolic lipid that inhibits both MCF-7 estrogen receptor α (ERα) positive and MDA-MB-231 triple negative breast cancer (TNBC) cell proliferation with IC50s of 13.5 and 35 μM, respectively. To identify potential mediators of AnAc action in breast cancer, we profiled the genome-wide microRNA transcriptome (microRNAome) in these two cell lines altered by the AnAc 24:1n5 congener. Whole genome expression profiling (RNA-seq) and subsequent network analysis in MetaCore Gene Ontology (GO) algorithm was used to characterize the biological pathways altered by AnAc. In MCF-7 cells, 69 AnAc-responsive miRNAs were identified, e.g., increased let-7a and reduced miR-584. Fewer, i.e., 37 AnAc-responsive miRNAs were identified in MDA-MB-231 cells, e.g., decreased miR-23b and increased miR-1257. Only two miRNAs were increased by AnAc in both cell lines: miR-612 and miR-20b; however, opposite miRNA arm preference was noted: miR-20b-3p and miR-20b-5p were upregulated in MCF-7 and MDA-MB-231, respectively. miR-20b-5p target EFNB2 transcript levels were reduced by AnAc in MDA-MB-231 cells. AnAc reduced miR-378g that targets VIM (vimentin) and VIM mRNA transcript expression was increased in AnAc-treated MCF-7 cells, suggesting a reciprocal relationship. The top three enriched GO terms for AnAc-treated MCF-7 cells were B cell receptor signaling pathway and ribosomal large subunit biogenesis and S-adenosylmethionine metabolic process for AnAc-treated MDA-MB-231 cells. The pathways modulated by these AnAc-regulated miRNAs suggest that key nodal molecules, e.g., Cyclin D1, MYC, c-FOS, PPARγ, and SIN3, are targets of AnAc activity.

Association of miR-196a-2 and miR-499 variants with ulcerative colitis and their correlation with expression of respective miRNAs

Background and aim

MicroRNAs are small non-coding RNAs that play an important role in regulating the gene expression of their target genes. SNP miR-196a-2 rs11614913 and miR-499 rs3746444 are reported to have association with the risk and prognosis of multiple-types of inflammatory diseases including IBD. This study was conducted to show if any association of SNP miR-196a-2rs11614913 and miR-499 rs3746444 exists with ulcerative colitis (UC) patients of north Indian population and how these polymorphisms modulate the expression profile of the respective miRNAs.

Methods

A total of 638 participants including 197 UC patients and 441 controls were included in this study. Polymorphisms were genotyped by PCR-RFLP and the miRNA expression was measured using qRT-PCR. Genotypes and allele frequencies were calculated using SPSS 16 software.

Results

MiR-196a-2 rs11614913 (C>T) and miR-499 rs3746444 (T>C) were found to be associated with UC. TT genotype of miR-196a-2 rs11614913 (p = 0.03) was negatively associated with UC whereas the heterozygous TC genotype of miR-499 rs3746444 (p = 0.003) was showing positive association with UC. Patients having a combination of both SNPs, developed disease at older age and they suffered from severe disease extent. Genotype that showed association with the disease also showed correlation with the changes in miRNA expression.

Conclusion

In this study we found miR-196a-2 rs11614913 and miR-499 rs3746444 were associated with UC in north Indian population. We found the genotype that showed association with UC also altered the expression of respective miRNA in the patient harboring the genotype. There was correlation between associated genotype and altered miRNA expression.

MicroRNA Gene Polymorphisms in Evaluating Therapeutic Efficacy After Transcatheter Arterial Chemoembolization for Primary Hepatocellular Carcinoma

OBJECTIVE

This study aimed to investigate the value of microRNA (miR) gene polymorphisms in evaluating the efficacy of transcatheter arterial chemoembolization (TACE) in primary hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

A total of 507 patients with primary HCC were enrolled at our hospital from August 2010 to December 2014. All of them received TACE and were divided into either an effective treatment group (237 cases), or an ineffective group (270 cases) according to the treatment efficacy. Polymerase chain reaction-restriction fragment length polymorphism was used to genotype the single-nucleotide polymorphisms of miR-196a2 rs11614913, miR-146a rs2910164, miR-499a rs3746444, and miR-149 rs2292832, and the genotypes and allele frequencies between the two groups were compared.

RESULTS

The frequencies of the CC genotype of miR-196a2 (rs11614913) and the GG genotype of miR-499a (rs3746444) were significantly higher in the ineffective group than in the effective group (both p < 0.05). For miR-196a2 (rs11614913), the overall survival (OS) of patients with the TT genotype was higher than patients with the CT+CC genotypes (p < 0.05); for miR-499a (rs3746444), the OS of patients with the AA genotype was higher than patients with the AG+GG genotypes (p < 0.05). MiR-196a2 rs11614913, miR-499a rs3746444, hepatitis B surface antigen (HbsAg), hepatitis B history, and Child-Pugh classification were independent prognostic factors for OS (all p < 0.05).

CONCLUSION

MiR-196a2 rs11614913 and miR-499a rs3746444 were significantly associated with a curative effect and a positive prognosis of TACE for primary HCC.

Association between microRNA polymorphisms and the risk of inflammatory bowel disease

Common single nucleotide polymorphisms (SNPs) in precursor microRNAs may change their properties via altering the expression of miRNAs, resulting in diverse functional consequences. The present study evaluated the effects of four common SNPs in pro-miRNAs on the risk of inflammatory bowel disease (IBD) and IBD‑associated colorectal cancer (IBD-CRC). In a hospital based case‑control investigation in a Chinese population, 468 patients with IBD and 450 age- and gender-matched healthy subjects were enrolled in the present study. The SNPs were genotyped using a polymerase chain reaction (PCR)-restriction fragment length polymorphism technique. The expression levels of the miRNAs were detected by reverse transcription‑PCR. For rs2910164, the risk of IBD was significantly increased in the GC and CC genotypes. The mean expression levels of mir‑146a in the CC and GC genotypes were lower, compared with that of the GG genotype. For rs2292832, an increased risk of IBD was detected in the recessive model of the TT genotype, compared with the combination of the CT and CC genotypes. The [T] allele was found to be at increased significantly, with a 1.268‑fold increased risk of IBD, compared with the [C] allele. The mean expression levele of mir‑149 expression level in the TT genotype was lower, compared with that of the CC genotype. For rs11614913, the risk of IBD‑CRC was significantly increased in the CC genotype, compared with the TT genotype. In the dominant model, the CC genotype had a high risk of IBD‑CRC, compared with the combination of the CT and TT genotypes. These findings suggested that mir-146a rs2910164 and mir‑149 rs2292832 may be associated with the increased risk of IBD via alterations in the expression levels of miRNAs. Therefore, mir‑196a rs11614913 may contribute to the progression of IBD-CRC.

Association between single nucleotide polymorphism in miR-499, miR-196a2, miR-146a and miR-149 and prostate cancer risk in a sample of Iranian population

MicroRNAs (miRNAs) play an important role in regulating gene expression at the post-transcriptional level and are involved in numerous physiological processes. Accumulating evidence suggests that single-nucleotide polymorphisms (SNPs) in human miRNA genes may affect miRNA biogenesis pathway and influence the susceptibility to several diseases such as cancer. The present study aimed to evaluate the impact of miR-499 rs3746444, miR-196a2 rs11614913, miR-149 rs2292832, and miR-146a rs2910164 polymorphisms on prostate cancer (PCa) risk in a sample of Iranian population. This case-control study was done on 169 patients with pathologically confirmed PCa and 182 benign prostatic hyperplasia (BPH). The genotyping assays were done using T-ARMS-PCR or PCR-RFLP methods. The findings indicated that CC genotype of miR-499 rs3746444 polymorphism increased the risk of PCa (OR = 1.76, 95% CI = 1.12-2.79, P = 0.019) compared to TT genotype. No statistically significant association was found between miR-196a2 rs11614913, miR-149 rs2292832, and miR-146a rs2910164 polymorphisms and PCa risk. In summary, the findings indicated that miR-499 rs3746444 polymorphism increased the risk of PCa in an Iranian population. Further studies with larger sample sizes and different ethnicities are necessary to verify the findings of the present study.

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

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

Genetic polymorphisms in miRNAs and susceptibility to colorectal cancer

The associations of SNPs rs11614913, rs2292832, and rs2910164 in miRNAs have been exploded in several independent studies and meta-analyses, but the small sample sizes and incomplete data precluded well-defined roles of the miRNA SNPs in the development of CRC. The aim of this study was to combine all available data to comprehensively assess the unclear association. A meta-analysis of nine studies included 2,209 cancers and 2,803 controls, 2,349 cases and 2,663 controls, and 1,409 cases and 1,115 controls for SNP rs11614913, SNP rs2910164, and SNP rs2292832, respectively. The true effect size was estimated by an odds ratio (OR) and 95 % confidence intervals (CI) with the fixed effects model. For SNP rs11614913, the risk of CRC was more pronounced in the C allele carriers as compared with the T allele carriers among the subjects of Asian decent (CC vs. TT: OR = 1.18, 95% CI 1.01-1.38, P = 0.734; CC vs. TC + TT: OR = 1.18, 95% CI 1.02-1.36, P = 0.573; C vs. T: OR = 1.08, 95% CI 1.00-1.17, P = 0.775). SNP rs2910164 and SNP rs2292832 were not found to be significantly associated with CRC risk. This meta-analysis reveals that SNP rs11614913, but not SNP rs2910164 and SNP rs2292832, may contribute to susceptibility to CRC in an Asian-specific manner.

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.

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

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

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.

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 between single nucleotide polymorphisms in miRNA196a-2 and miRNA146a and susceptibility to hepatocellular carcinoma in a Chinese population

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers in the world and deeply threatens people's health, especially in China. Techniques of early diagnosis, prevention and prediction are still being discovered, among which the approaches based on single nucleotide polymorphisms in microRNA genes (miRNA SNPs) are newly proposed and show prospective potential. In particular, the association between SNPs in miRNA196a-2 (rs11614913) and miRNA146a (rs2910164) and HCC has been investigated. However, the conclusions made were conflicting, possibly due to insufficient sample size or population stratification. Further confirmations in well-designed large samples are still required. In this study, we verified the association between these two SNPs and the susceptibility to HCC by MassARRAY assay in a 2,000 large Chinese case-control sample. Significant association between rs11614913 and HCC was confirmed. Subjects with the genotype of CT+TT or T allele in rs11614913 were more resistant to HCC (CT+TT: OR (95% CI)=0.73 (0.57-0.92), P=0.01; T allele: OR (95% CI)=0.85 (0.75-0.97), P=0.02) and HBV-related HCC (CT+TT: OR (95% CI)=0.69 (0.53-0.90), P=0.01; T allele: OR (95% CI)=0.82 (0.71-0.95), P=0.01). The affected carriers of CT or TT also tended to have lower levels of serum AFP (P=0.01). This study demonstrated a role of rs11614913 in the etiology of HCC. Further research should focus on the clinical use of this miRNA SNP, so as to facilitate conquering HCC.

Associations of single nucleotide polymorphisms in miR-146a, miR-196a, miR-149 and miR-499 with colorectal cancer susceptibility

BACKGROUND

MicroRNAs (miRNAs) are an abundant class of endogenous small non-coding RNAs of 20-25 nucleotides in length that function as negative gene regulators. MiRNAs play roles in most biological processes, as well as diverse human diseases including cancer. Recently, many studies investigated the association between SNPs in miR-146a rs2910164, miR-196a2 rs11614913, miR-149 rs229283, miR-499 rs3746444 and colorectal cancer (CRC), which results have been inconclusive.

METHODOLOGY/PRINCIPAL FINDINGS

PubMed, EMBASE, CNKI databases were searched with the last search updated on November 5, 2013. For miR-196a2 rs11614913, a significantly decreased risk of CRC development was observed under three genetic models (dominant model: OR = 0.848, 95%CI: 0.735-0.979, P = 0.025; recessive model: OR = 0.838, 95%CI: 0.721-0.974, P = 0.021; homozygous model: OR = 0.754, 95%CI: 0.627-0.907, P = 0.003). In the subgroup analyses, miR-196a2*T variant was associated with a significantly decreased susceptibility of CRC (allele model: OR = 0.839, 95%CI: 0.749-0.940, P = 0.000; dominant model: OR = 0.770, 95%CI: 0.653-0.980, P = 0.002; recessive model: OR = 0.802, 95%CI: 0.685-0.939, P = 0.006; homozygous model: OR = 0.695, 95%CI: 0.570-0.847, P = 0.000). As for miR-149 rs2292832, the two genetic models (recessive model: OR = 1.199, 95% CI 1.028-1.398, P = 0.021; heterozygous model: OR = 1.226, 95% CI 1.039-1.447, P = 0.013) demonstrated increased susceptibility to CRC. On subgroup analysis, significantly increased susceptibility of CRC was found in the genetic models (recessive model: OR = 1.180, 95% CI 1.008-1.382, P = 0.040; heterozygous model: OR = 1.202, 95% CI 1.013-1.425, P = 0.013) in the Asian group.

CONCLUSIONS

These findings supported that the miR-196a2 rs11614913 and miR-149 rs2292832 polymorphisms may contribute to susceptibility to CRC.

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.

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

Objective

MicroRNAs (miRNAs) are short regulatory RNAs that can modulate gene expression and function as negative regulators. Common genetic variants like single nucleotide polymorphisms (SNPs) in miRNA genes may alter their expression or maturation resulting in varied functional consequences in carcinogenesis. Therefore, we evaluated the genetic variants in pre-miRNAs: hsa-miR-146a G/C (rs2910164), hsa-miR-196a2 C/T (rs11614913), and hsa-miR-499 T>C (rs3746444) for their role in breast cancer susceptibility.

Study design

The study comprised 121 breast cancer patients, 115 with benign breast disease, and 164 controls. The genotypic frequency of miRNA polymorphisms was determined by PCR-RFLP assay. Logistic regression was used for statistical analysis using SPSS Software version 15.0. In silico analysis was done using various bioinformatics tools (F-SNP, FAST-SNP).

Results

The heterozygous variant of miR-146a G/C (rs2910164) is associated with the reduced risk of breast cancer at the genotype level as well as at the allele level (p < 0.05, OR = 0.5) as compared to controls. On the contrary, no significant difference was observed in the distribution of miR-196a2 C/T (rs11614913) and miR-499 T>C (rs3746444) polymorphisms in any groups both at genotype and allele levels. On the other hand, in multivariate analysis, we found that the miR-196a2 (rs11614913) C>T was associated with an increased risk of breast cancer risk in postmenopausal females (p = 0.02, OR = 3.2). We also attempted to find out the risk of malignant breast disease in relation to each of the above SNPs on dividing our data on the basis of benign and malignant status, but no significant difference was observed. In silico analysis using F-SNP showed change in transcriptional regulation by miR-146a G/C (rs2910164), miR-196a2 C/T (rs11614913) and miR-499 T>C (rs3746444) variations; the functional score was 0.100, 0.065 and 0.277, respectively.

Conclusion

The results of the present study demonstrate that miR-146a G/C (rs2910164) polymorphism is associated with reduced genetic susceptibility to breast cancer. However, multivariate analysis showed as miR-196a2 (rs11614913) C>T to be associated with increased risk of breast cancer risk in postmenopausal females. Further multicentric studies involving a large number of cases need to be carried out to strengthen the present results.

Clinical importance of recently discovered gene variants in colon cancer recurrence and prognosis

SUMMARY 

Colorectal cancer survival has increased over the past few years, mainly due to the advances in the metastatic setting. Nonetheless, in the adjuvant scenario, minor improvements have been made, as the tumor's anatomopathological features remain to be most important factors for predicting the risk of recurrence and the prognosis. A deeper understanding of the molecular mechanisms involved in colorectal carcinogenesis, progression, invasion and metastasis development, have laid the groundwork for the search of genetic biomarkers that can help identify patients at a higher risk of recurrence. Common germline variants in genes within molecular pathways responsible for cancer development and progression have proven to influence the probability of relapse and the patient's prognosis. Here, we systematically review the relevance of genetic variants as prognostic biomarkers in colorectal carcinoma.

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.

Are pre-miR-146a and PTTG1 associated with papillary thyroid cancer?

Papillary thyroid carcinoma (PTC) is the most common endocrine malignancy, with a steadily increasing incidence in the last few decades worldwide. The predisposition to developing this carcinoma by the heterozygous state of rs2910164 within the precursor of the miR-146a has been reported, but recently not confirmed. Interestingly, on the same chromosome, almost 50 kb separate the pre-miR-146a from the pituitary tumor-transforming gene 1 (PTTG1), a proto-oncogene involved in several tumors, including thyroid cancers. In this study, we analyzed, using a case-control design, the genetic association between PTC and the genomic region encompassing pre-miR-146a rs2910164 and PTTG1 rs1862391 and rs2910202. We enrolled 307 affected patients and 206 healthy controls. The possible presence of thyroid nodules in controls was excluded by ultrasonography. All the cases were submitted to single-nucleotide polymorphism (SNP) genotyping of pre-miR-146a and PTTG1, and risk association analyses were carried out. The genotypic and allelic frequencies of pre-miR-146a rs2910164 were not statistically different in the patients and controls, and this SNP was not in linkage disequilibrium with the investigated PTTG1 SNPs. Consistently, meta-analyses, the first including all the affected cases published to date, did not confirm the previously reported association of the heterozygous CG genotype with PTC. The PTTG1 SNPs exhibited the same allelic frequency in the patients and controls and were not associated with the disease. In conclusion, in a well-selected Italian population, neither pre-miR-146a rs2910164 nor PTTG1 rs1862391 and rs2910202 were found to be associated with the risk of developing PTC.