The Hsa-miR-27a rs895819 (A>G) polymorphism and cancer susceptibility

Functional Variants in MicroRNAs (rs895819, rs11614913 and rs2910164) Are Associated with Susceptibility and Clinicopathological Features in Mexican Patients with Colorectal Cancer

BACKGROUND

miRNAs are non-coding RNAs participating actively in the post-translational regulation of oncogenes, tumor suppressor, and DNA repair genes implicated in colorectal cancer (CRC). This study aims to examine the association of the variants miR-27a (rs895819 A>G), miR-196a2 (rs11614913 T>G) and miR-146a (rs2910164 C>G) in Mexican CRC patients.

METHODS

DNA samples from 183 patients and 186 healthy Mexican subjects were analyzed. Variants were identified by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methodology. Association was calculated by the odds ratio (OR) and adjusted by the Bonferroni test.

RESULTS

Patients carrying the G/G genotype of the rs895819 variant in the miR-27a gene showed an increased risk of CRC (19% vs 12%, P=0.013). A similar tendency was noticed for patients younger than 50 years carrying A/G (48% vs 41%, P=0.014). The A/G genotype in TNM stages I+II (55.7% vs 40.8%, P=0.011) and tumor location in the colon (69.5 vs 40.8%, P=0.001) were also increased. For the variant rs11614913 of the miR-196a2 gene, carriers of the C/C genotype showed an increased risk of CRC (32% vs 22%, P=0.009). This genotype was more frequent in TNM stage III+IV (36.8% vs 22.5%, P=0.007) and the tumor had a more recurrent location in the rectum (31.6% vs 22.5%, P=0.013). The rs2910164 variant of the miR-146a gene was found to have no significant risk associations.

CONCLUSION

Our results reveal that the rs895819 variant in miR-27a and rs11614913 in miR-196a2 have a substantial impact on the development of CRC.

Uncovering the expression patterns and the clinical significance of miR-182, miR-205, miR-27a and miR-369 in patients with urinary bladder cancer

BACKGROUND

Given the high recurrence and progression rates and the absence of reliable markers for early detection and prognosis prediction of patients with urothelial bladder cancer (BCa), the exploration of new biomarkers with high specificity is imperative. Mainly, microRNAs (miRNAs), which are involved in the initiation and the progression of BCa. Herein, the expression patterns of miR-182, miR-205, miR-27a and miR-369 were evaluated in patients with urothelial BCa.

METHODS AND RESULTS

The expression levels of the miRNAs were investigated in 90 FFPE tissue samples (23 LG NMIBC, 44 HG NMIBC, 23 MIBC) and 10 non tumoral bladder tissues using TaqMan based RT-qPCR. Data analysis was performed using 2^-ΔΔCT method. Correlation to clinical characteristics of the patients was performed using descriptive statistics and the receiver operating characteristic (ROC) curve was performed to evaluate the diagnostic value of all miRNAs. MiR-27a, miR-205 and miR-369 were down-regulated whereas miR-182 was up-regulated in patients compared to controls (p < 0.001). MiR-205 and miR-182 positively segregate between NMIBC and MIBC (p = 0.002 and p = 0.000 respectively) whereas the distribution of miR-27a's expression among these tumor groups was almost significant (p = 0.05) and that of miR-369's expression was irrelevant (p = 0.618). Interestingly, miR-182 was discriminative between LG NMIBC and HG NMIBC (p < 0.001) and Ta/T1 tumors (p = 0.000). Furthermore, high levels of miR-182 were potentially predictive of progression in NMIBC patients (p = 0.01).

CONCLUSION

Collectively, a selection of miRNAs was found to be aberrantly expressed in BCa suggesting a potential diagnostic value in BCa. In addition, the clinical value of miR-182 and miR-205 as potential prognosis biomarkers was highlighted. Indeed, our data provide additional insights into cancer biology. Further functional or target studies are mandatory to strengthen these findings.

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.

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.

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.

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.

The Emerging Role of miRNAs and Their Clinical Implication in Biliary Tract Cancer

Biliary tract cancers are aggressive malignancies that include gallbladder cancer and tumors of intra- and extrahepatic ducts and have a poor prognosis. Surgical resection remains the main curative therapy. Nevertheless, numerous patients experience recurrence even after radical surgery. This scenario drives the research to identify biliary tract cancer biomarkers despite the limited progress that has been made. Recently, a large number of studies have demonstrated that deregulated expression of microRNAs is closely associated with cancer development and progression. In this review, we highlight the role and importance of microRNAs in biliary tract cancers with an emphasis on utilizing circulating microRNAs as potential biomarkers. Additionally, we report several single-nucleotide polymorphisms in microRNA genes that are associated with the susceptibility of biliary tract tumors.

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.

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.

MicroRNA-related sequence variations in human cancers

MicroRNAs are emerging as a most promising field in basic and translational research, explaining the pathogenesis of numerous human diseases and providing excellent tools for their management. This review considers the effects of microRNA sequence variations and their implication in pathogenesis and predisposition to human cancers. Although the role of microRNAs still remains to be elucidated, functional, and populational studies indicate that microRNA variants are important factors underlying the process of carcinogenesis. Further understanding of the cellular and molecular basis of microRNA action will lead to the identification of their new target genes and microRNA-regulated pathways. As a consequence, novel models of cancer pathogenesis can be proposed, and serve as a basis for elucidation of new prognostic and diagnostic tools for human cancers.