Associations of lifestyle-related factors, hsa-miR-149 and hsa-miR-605 gene polymorphisms with gastrointestinal cancer risk

Single Nucleotide Polymorphisms Associated with Prostate Cancer Progression: A Systematic Review

BACKGROUND

New biomarkers of progression in patients with prostate cancer (PCa) are needed to improve their classification and clinical management. This systematic review investigated the relationship between single nucleotide polymorphisms (SNPs) and PCa progression.

METHODS

A keyword search was performed in Pubmed, EMBASE, Scopus, Web of Science, and Cochrane for publications between 2007 and 2022. We included articles with adjusted and significant associations, a median follow-up greater than or equal to 24 months, patients taken to radical prostatectomy (RP) as a first therapeutic option, and results presented based on biochemical recurrence (BCR).

RESULTS

In the 27 articles selected, 73 SNPs were identified in 39 genes, organized in seven functional groups. Of these, 50 and 23 SNPs were significantly associated with a higher and lower risk of PCa progression, respectively. Likewise, four haplotypes were found to have a significant association with PCa progression.

CONCLUSION

This article highlights the importance of SNPs as potential markers of PCa progression and their possible functional relationship with some genes relevant to its development and progression. However, most variants were identified only in cohorts from two countries; no additional studies reproduce these findings.

Association of miR-149 T>C and miR-196a2 C>T Polymorphisms with Colorectal Cancer Susceptibility: A Case-Control Study

The principal aim of the current study was to investigate the relationship between miR-149 T>C (rs2292832) and miR-196a2 C>T (rs11614913) small non-coding RNA polymorphisms and the risk of developing CRC in the Azerbaijani population. The study included 120 patients diagnosed with CRC and 125 healthy individuals. Peripheral blood samples were collected from all the subjects in EDTA tubes and DNA extraction was performed by salting out. Polymorphisms were determined using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. While comparing without gender distinction no statistical correlation was found between the heterozygous TC (OR = 0.66; 95% CI = 0.37-1.15; p = 0.142), mutant CC (OR = 1.23; 95% CI = 0.62-2.45; p = 0.550), and mutant C (OR = 1.03; 95% CI = 0.72-1.49; p = 0.859) alleles of the miR-149 gene and the CT (OR = 1.23; 95% CI = 0.69-2.20; p = 0.485), mutant TT (OR = 1.29; 95% CI = 0.67-2.47; p = 0.452), and mutant T (OR = 1.17; 95% CI = 0.82-1.67; p = 0.388) alleles of the miR-196a2 gene and the risk of CRC. However, among women, miR-149 TC (OR = 0.43; 95% CI = 0.19-1.01; p = 0.048) correlated with a reduced risk of CRC, whereas miR-196a2 CT (OR = 2.77; 95% CI = 1.13-6.79; p = 0.025) correlated with an increased risk of CRC. Our findings indicated that miR-149 T>C (rs2292832) might play a protective role in the development of CRC in female patients, whereas the miR-196a2 (rs11614913) polymorphism is associated with an increased risk of CRC in women in the Azerbaijani population, highlighting the importance of gender dimorphism in cancer etiology.

Li–Fraumeni Syndrome: Mutation of TP53 Is a Biomarker of Hereditary Predisposition to Tumor: New Insights and Advances in the Treatment

Simple Summary

Li–Fraumeni Syndrome (LFS) is a rare tumor predisposition syndrome in which the tumor suppressor TP53 gene is mutated in the germ cell population. LFS patients develop a broad spectrum of cancers in their lifetime. The risk to develop these tumors is not decreased by any type of treatment and if the analysis of the TP53 mutational status in the family members was not possible, tumors are often diagnosed in already advanced stages. This review aims to report the evidence for novel mechanisms of tumor onset related to germline TP53 mutations and possible treatments.

Abstract

Li–Fraumeni syndrome (LFS) is a rare familial tumor predisposition syndrome with autosomal dominant inheritance, involving germline mutations of the TP53 tumor suppressor gene. The most frequent tumors that arise in patients under the age of 45 are osteosarcomas, soft-tissue sarcomas, breast tumors in young women, leukemias/lymphomas, brain tumors, and tumors of the adrenal cortex. To date, no other gene mutations have been associated with LFS. The diagnosis is usually confirmed by genetic testing for the identification of TP53 mutations; therefore, these mutations are considered the biomarkers associated with the tumor spectrum of LFS. Here, we aim to review novel molecular mechanisms involved in the oncogenic functions of mutant p53 in LFS and to discuss recent new diagnostic and therapeutic approaches exploiting TP53 mutations as biomarkers and druggable targets.

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.

Role of microRNAs in inflammatory upper airway diseases

MicroRNAs (miRNAs) are a conserved family of small endogenous noncoding RNA molecules that modulate post-transcriptional gene expression in physiological and pathological processes. miRNAs can silence target mRNAs through degradation or inhibition of translation, showing their pivotal role in the pathogenesis of many human diseases. miRNAs play a role in regulating immune functions and inflammation and are implicated in controlling the development and activation of T and B cells. Inflammatory chronic upper airway diseases, such as rhinitis and rhinosinusitis, are spread all over the world and characterized by an exaggerated inflammation involving a complex interaction between immune and resident cells. Until now and despite allergy, little is known about their etiology and the processes implicated in the immune response and tuning inflammation of these diseases. This review highlights the knowledge of the current literature about miRNAs in inflammatory chronic upper airways diseases and how this may be exploited in the development of new clinical and therapeutic strategies.

SARS-CoV-2 may regulate cellular responses through depletion of specific host miRNAs

Cold viruses have generally been considered fairly innocuous until the appearance of the severe acute respiratory coronavirus 2 (SARS-CoV-2) in 2019, which caused the coronavirus disease 2019 (COVID-19) global pandemic. Two previous viruses foreshadowed that a coronavirus could potentially have devastating consequences in 2002 [severe acute respiratory coronavirus (SARS-CoV)] and in 2012 [Middle East respiratory syndrome coronavirus (MERS-CoV)]. The question that arises is why these viruses are so different from the relatively harmless cold viruses. On the basis of an analysis of the current literature and using bioinformatic approaches, we examined the potential human miRNA interactions with the SARS-CoV-2's genome and compared the miRNA target sites in seven coronavirus genomes that include SARS-CoV-2, MERS-CoV, SARS-CoV, and four nonpathogenic coronaviruses. Here, we discuss the possibility that pathogenic human coronaviruses, including SARS-CoV-2, could modulate host miRNA levels by acting as miRNA sponges to facilitate viral replication and/or to avoid immune responses.

Genetic variants in microRNAs are associated with cervical cancer risk

Because genetic variants in microRNAs (miRNAs) or their surrounding regions can alter miRNA processing, expression and final biological function, we investigated whether miRNA single-nucleotide polymorphisms (SNPs) are associated with cervical cancer (CC) susceptibility. Common miRNA SNPs (i.e. miR-146a rs2910164, miR-149 rs2292832, miR-196a2 rs11614913, miR-499 rs3746444, miR-605 rs2043556 and miR-618 rs2682818) were genotyped in the 954 patients and 1339 controls. The results showed that the miR-149 rs2292832 TC/CC genotypes were associated with a 21% increased risk of CC compared with the TT genotype [odds ratio (OR) = 1.21, 95% confidence interval (CI) = 1.00-1.47]. The association was more prominent among the subjects with age ≤ 48 years (OR = 1.55, 95% CI = 1.16-2.06), having history of abortion (OR = 1.44, 95% CI = 1.12-1.86), premenopausal status (OR = 1.41, 95% CI = 1.08-1.85) and patients with clinical stage II of CC (OR = 1.43, 95% CI = 1.08-1.90). The expression plasmids containing the pre-miR-149 sequence with C allele of rs2292832 transcribed higher amount of mature miR-149-5p/3p than these with T allele in the HeLa and SiHa cells. Therefore, the rs2292832 polymorphism might influence CC susceptibility through modulation of the procession of pre-miR-149 to mature miRNAs.

Association of mir-196a-2 rs11614913 and mir-149 rs2292832 Polymorphisms With Risk of Cancer: An Updated Meta-Analysis

Background: Accumulating evidence suggests that functional dysregulations of miRNAs, especially miR-196a-2 and miR-149, in cancers could be attributed to polymorphisms in miRNA sequences. This study was aimed at clarifying the association of mir-196a-2 rs11614913 and mir-149 rs2292832 with cancer risk by performing an updated meta-analysis of genetic association studies. Methods: PubMed, Embase, Scopus, and ScienceDirect databases were searched until 9 April 2018 to identify eligible studies. Studies should meet the following criteria to be included in the meta-analysis: evaluation of genetic association between rs11614913 and/or rs2292832 and susceptibility to cancer; A case-control design; Written in English; Availability of sufficient data for estimating odds ratio (OR) and its 95% confidence interval (95%CI). Studies that met the following criteria were excluded: review articles, meta-analysis, abstracts or conference papers; duplicate publications; studies on animals or cell-lines; studies without a case-control design; studies that did not report genotype frequencies. Pooled ORs and 95% CIs were estimated using a total of 111 studies (41,673 cases and 49,570 controls) for mir-196a rs11614913 and 44 studies (15,954 cases and 19,594 controls) for mir-149 rs2292832. Stratified analysis according to quality scores, genotyping method, ethnicity, broad cancer category and cancer type was also performed. Results: Mir-196a-2 rs11614913 T allele was associated with decreased cancer risk in overall population. The association was only significant in Asians but not Caucasians. In subgroup analysis, significant associations were found in high quality studies, gynecological cancers, ovarian, breast, and hepatocellular cancer. Mir-149 rs2292832 was not associated with cancer risk in overall population and there were no differences between Asians and Caucasians. However, the T allele was associated with a decrease risk of gastrointestinal tract cancers under the heterozygote model and an increased risk of colorectal cancer under the recessive model. Conclusions: The present meta-analysis suggests that mir-196a-2 rs11614913 may contribute to the risk of cancer especially in Asians. Mir-149 rs2292832 may modulate the risk of gastrointestinal tract cancers especially colorectal cancer. This study had some limitations such as significant heterogeneity in most contrasts, limited number of studies enrolling Africans or Caucasians ancestry and lack of adjustment for covariates and environmental interactions.

Lack of Association between miR-605 rs2043556 Polymorphism and Overall Cancer Risk: A Meta-analysis of Case-control Studies

Growing evidence propose an association between miRNA polymorphisms and cancer susceptibility. This study aimed to examine the impact of miR-605 rs2043556 polymorphism on cancer risk through a meta-analysis based on 3198 cancer cases and 4943 controls. Eligible studies were retrieved by searching Web of Science, PubMed, Scopus, and Google Scholar databases up to August 27, 2018. The pooled Odds Ratios (ORs) with 95% Confidence Intervals (CIs) were calculated using a random-effect model to estimate the strength of association between rs2043556 variant of miR-605 and cancer risk. Overall, no significant association was found between miR-605 rs2043556 polymorphism and cancer risk in heterozygous codominant (OR=0.93, 95% CI=0.76-1.13, p=0.44, AG vs. AA), homozygous codominant (OR=1.01, 95%CI=0.78-1.30, p=0.94, GG vs. AA), dominant (OR=0.95, 95% CI=0.79-1.13, p=0.55, AG+GG vs. AA), recessive (OR=1.07, 95%CI=0.84-1.38, p=0.57, GG vs. AG+AA), overdominant (OR=0.93, 95% CI=0.76-1.12, p=0.43, AG vs. GG+AA), and allele (OR=0.98, 95% CI=0.87-1.10, p=0.73, G vs. A) genetic models tested. Stratified analysis by cancer type revealed that the rs2043556 variant was not associated with digestive tract cancer, breast cancer, gastric cancer as well as lung cancer. Taken together, the findings of this meta-analysis did not support an association between miR-605 rs2043556 polymorphism and cancer susceptibility.

Regulation and functions of MicroRNA-149 in human cancers

MicroRNAs are small non-coding RNAs that play critical roles in the regulatory mechanisms involving cell differentiation, proliferation, apoptosis and tumorigenesis. Recent research efforts have been conducted to apply these discoveries into clinical functions, including the early diagnosis and therapeutic outcome of patients with cancer. Previous studies have shown that microRNA-149 (miR-149) is dysregulated in various human cancers and exerts its effects on tumorigenesis and tumour progression. In this review, we summarized the potential roles of miR-149 dysregulation and its target genes during tumorigenesis and clinical treatment of human cancers.

Functional miRNA variants affect lung cancer susceptibility and platinum-based chemotherapy response

Background

Platinum-based chemotherapy is widely used as the first-line treatment of lung cancer. MicroRNAs have an important role in lung carcinogenesis and progression. Single-nucleotide polymorphisms (SNPs) in miRNA involved in miRNA biogenesis and structural alteration may affect miRNA expression. In this study, we aimed to investigate the association of functional miRNA variants with the lung cancer susceptibility and platinum-based chemotherapy response.

Methods

Nine genetic polymorphisms in miR-605, 146a, 149, 196a-2, 27a, 499, 30c-1, 5197 and let-7a-2 were selected with comprehensive collection strategy and genotyped by MALDI-TOF mass spectrometry in a total of 215 health control and 507 lung cancer patients (386 patients received at least two consecutive cycles of platinum-based chemotherapy).

Results

We found that an allele carriers of miR-146a rs2910164 (P=0.022, OR=1.315) and C allele carriers of miR-149 rs71428439 (P=0.042, OR=1.372) performance a high risk of lung cancer. Mir-30c-1 rs928508 (P=0.005, in recessive model) and let-7a-2 rs629367 (P=0.030 and P=0.021, in additive and dominant models, respectively) showed strong relationship with lung cancer risk in age under 57 years. The rs11614913 (miR-196a-2) C allele or rs9280508 (miR-30c-1) G allele carriers shown more sensitive to platinum both in additive (P=0.010, P=0.022, respectively) and dominant models (P=0.001, P=0.018, respectively).

Conclusions

These findings suggested that SNPs rs71428439 (miR-149), rs2910164 (miR-146a), rs928508 (mir-30c-1) and rs629367 (let-7a-2) were associated with the lung cancer prevalence, polymorphisms of rs11614913 (miR-196a-2) and rs9280508 (miR-30c-1) significantly influenced the patients' response to platinum-based chemotherapy, which may serve as potential clinical biomarkers to predict lung cancer risk and platinum-based chemotherapy response.

miR-149 in Human Cancer: A Systemic Review

MicroRNAs (miRNAs) are small noncoding RNAs that regulate post-transcriptional gene expression via binding to the 3'-untranslated region (3'-UTR) of targeted mRNAs. They are reported to play important roles in tumorigenesis and progression of various cancers. Among them, miR-149 was confirmed to be aberrantly regulated in various tumors. In this review, we provide a complex overview of miR-149, particularly summarize the critical roles of it in cancers and expect to lay the foundation for future works on this important microRNA.

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.

Plant Lectins as Medical Tools against Digestive System Cancers

Digestive system cancers-those of the esophagus, stomach, small intestine, colon-rectum, liver, and pancreas-are highly related to genetics and lifestyle. Most are considered highly mortal due to the frequency of late diagnosis, usually in advanced stages, caused by the absence of symptoms or masked by other pathologies. Different tools are being investigated in the search of a more precise diagnosis and treatment. Plant lectins have been studied because of their ability to recognize and bind to carbohydrates, exerting a variety of biological activities on animal cells, including anticancer activities. The present report integrates existing information on the activity of plant lectins on various types of digestive system cancers, and surveys the current state of research into their properties for diagnosis and selective treatment.

MicroRNA-605 functions as a tumor suppressor by targeting INPP4B in melanoma

MicroRNAs (miRNAs) play crucial roles in the initiation and progression of various cancers, including melanoma. Recently, the genetic variants and deregulation of miR-605 have been reported to participate in carcinogenesis. However, the expression status of the miR-605 in melanoma tissues and its role in melanoma progression remain unknown. In this study, we found that miR-605 was significantly downregulated in melanoma cell lines and clinical specimens. Further function studies demonstrated that miR-605 suppressed melanoma cell growth both in vitro and in vivo. Moreover, INPP4B gene was identified as a target of miR-605 through bioinformatics analysis and luciferase reporter assays. Further analysis demonstrated that the inhibition of INPP4B mediated SGK3 activation was required for the suppressive role of miR-605 on melanomas cell growth. Collectively, our data suggest that miR-605 functions as a tumor suppressor by negatively regulating INPP4B mediated SGK3 activation in melanoma and may present a potential target for therapeutic intervention.

The Drosophila foraging gene human orthologue PRKG1 predicts individual differences in the effects of early adversity on maternal sensitivity

There is variation in the extent to which childhood adverse experience affects adult individual differences in maternal behavior. Genetic variation in the animal foraging gene, which encodes a cGMP-dependent protein kinase, contributes to variation in the responses of adult fruit flies, Drosophila melanogaster, to early life adversity and is also known to play a role in maternal behavior in social insects. Here we investigate genetic variation in the human foraging gene (PRKG1) as a predictor of individual differences in the effects of early adversity on maternal behavior in two cohorts. We show that the PRKG1 genetic polymorphism rs2043556 associates with maternal sensitivity towards their infants. We also show that rs2043556 moderates the association between self-reported childhood adversity of the mother and her later maternal sensitivity. Mothers with the TT allele of rs2043556 appeared buffered from the effects of early adversity, whereas mothers with the presence of a C allele were not. Our study used the Toronto Longitudinal Cohort (N=288 mother-16 month old infant pairs) and the Maternal Adversity and Vulnerability and Neurodevelopment Cohort (N=281 mother-18 month old infant pairs). Our findings expand the literature on the contributions of both genetics and gene-environment interactions to maternal sensitivity, a salient feature of the early environment relevant for child neurodevelopment.

Role of miRNAs and their potential to be useful as diagnostic and prognostic biomarkers in gastric cancer

Alterations in epigenetic control of gene expression play an important role in many diseases, including gastric cancer. Many studies have identified a large number of upregulated oncogenic miRNAs and downregulated tumour-suppressor miRNAs in this type of cancer. In this review, we provide an overview of the role of miRNAs, pointing to their potential to be useful as diagnostic and/or prognostic biomarkers in gastric cancer. Moreover, we discuss the influence of polymorphisms and epigenetic modifications on miRNA activity.

Association of microRNA polymorphisms with the risk of head and neck squamous cell carcinoma in a Chinese population: a case-control study

BACKGROUND

MicroRNA (miRNA) polymorphisms may alter miRNA-related processes, and they likely contribute to cancer susceptibility. Various studies have investigated the associations between genetic variants in several key miRNAs and the risk of human cancers; however, few studies have focused on head and neck squamous cell carcinoma (HNSCC) risk. This study aimed to evaluate the associations between several key miRNA polymorphisms and HNSCC risk in a Chinese population.

METHODS

In this study, we genotyped five common single-nucleotide polymorphisms (SNPs) in several key miRNAs (miR-149 rs2292832, miR-146a rs2910164, miR-605 rs2043556, miR-608 rs4919510, and miR-196a2 rs11614913) and evaluated the associations between these SNPs and HNSCC risk according to cancer site with a case-control study including 576 cases and 1552 controls, which were matched by age and sex in a Chinese population.

RESULTS

The results revealed that miR-605 rs2043556 [dominant model: adjusted odds ratio (OR) 0.71, 95% confidence interval (CI) 0.58-0.88; additive model: adjusted OR 0.74, 95% CI 0.62-0.89] and miR-196a2 rs11614913 (dominant model: adjusted OR 1.36, 95% CI 1.08-1.72; additive model: adjusted OR 1.28, 95% CI 1.10-1.48) were significantly associated with the risk of oral squamous cell carcinoma (OSCC). Furthermore, when these two loci were evaluated together based on the number of putative risk alleles (rs2043556 A and rs11614913 G), a significant locus-dosage effect was noted on the risk of OSCC (P trend < 0.001). However, no significant association was detected between the other three SNPs (miR-149 rs2292832, miR-146a rs2910164, and miR-608 rs4919510) and HNSCC risk.

CONCLUSION

Our study provided the evidence that miR-605 rs2043556 and miR-196a2 rs11614913 may have an impact on genetic susceptibility to OSCC in Chinese population.

miR-149 controls non-alcoholic fatty liver by targeting FGF-21

Non‐alcoholic fatty liver disease (NAFLD), a lipid metabolism disorder characterized by the accumulation of intrahepatic fat, has emerged as a global public health problem. However, its underlying molecular mechanism remains unclear. We previously have found that miR‐149 was elevated in NAFLD induced by high‐fat diet mice model, whereas decreased by a 16‐week running programme. Here, we reported that miR‐149 was increased in HepG2 cells treated with long‐chain fatty acid (FFA). In addition, miR‐149 was able to promote lipogenesis in HepG2 cells in the absence of FFA treatment. Moreover, inhibition of miR‐149 was capable of inhibiting lipogenesis in HepG2 cells in the presence of FFA treatment. Meanwhile, fibroblast growth factor‐21 (FGF‐21) was identified as a target gene of miR‐149, which was demonstrated by the fact that miR‐149 could negatively regulate the protein expression level of FGF‐21, and FGF‐21 was also responsible for the effect of miR‐149 inhibitor in decreasing lipogenesis in HepG2 cells in the presence of FFA treatment. These data implicate that miR‐149 might be a novel therapeutic target for NAFLD.

Polymorphisms in pre-miRNA genes and cooking oil fume exposure as well as their interaction on the risk of lung cancer in a Chinese nonsmoking female population

BACKGROUND

MicroRNAs (miRNAs) are suggested to be very important in the development of lung cancer. This study assesses the association between polymorphisms in miRNA-related (miR)-26a-1, miR-605, and miR-16-1 genes and risk of lung cancer, as well as the effect of gene-environment interaction between miRNA polymorphisms and cooking fume exposure on lung cancer.

METHODS

A case-control study including 268 diagnosed nonsmoking female lung cancer patients and 266 nonsmoking female controls was carried out. Three miRNA polymorphisms (miR-26a-1 rs7372209, miR-605 rs2043556, and miR-16-1 rs1022960) were analyzed. Both additive and multiplicative interactions were assessed.

RESULTS

MiR-16-1 rs1022960 may be associated with the risk of lung cancer. Carriers with TT genotype of miR-16-1 rs1022960 were observed to have a decreased risk of lung cancer compared with CC and CT genotype carriers (odds ratio =0.550, 95% confidence interval =0.308-0.983, P=0.044). MiR-26a-1 rs7372209 and miR-605 rs2043556 showed no statistically significant associations with lung cancer risk. There were no significant associations between the three single nucleotide polymorphisms and lung adenocarcinoma. People with exposure to both risk genotypes of miR-26a-1 rs7372209 and cooking oil fumes were more likely to develop lung cancer than those with only genetic risk factor or cooking oil fumes (odds ratios were 2.136, 1.255, and 1.730, respectively). The measures of biological interaction and logistic models indicate that gene-environment interactions were not statistically significant on additive scale or multiplicative scale.

CONCLUSION

MiR-16-1 rs1022960 may be associated with the risk of lung cancer in a Chinese nonsmoking female population. The interactions between miRNA polymorphisms (miR-26a-1 rs7372209, miR-605 rs2043556, and miR-16-1 rs1022960) and cooking oil fumes were not statistically significant.

MicroRNAs in Breastmilk and the Lactating Breast: Potential Immunoprotectors and Developmental Regulators for the Infant and the Mother

Human milk (HM) is the optimal source of nutrition, protection and developmental programming for infants. It is species-specific and consists of various bioactive components, including microRNAs, small non-coding RNAs regulating gene expression at the post-transcriptional level. microRNAs are both intra- and extra-cellular and are present in body fluids of humans and animals. Of these body fluids, HM appears to be one of the richest sources of microRNA, which are highly conserved in its different fractions, with milk cells containing more microRNAs than milk lipids, followed by skim milk. Potential effects of exogenous food-derived microRNAs on gene expression have been demonstrated, together with the stability of milk-derived microRNAs in the gastrointestinal tract. Taken together, these strongly support the notion that milk microRNAs enter the systemic circulation of the HM fed infant and exert tissue-specific immunoprotective and developmental functions. This has initiated intensive research on the origin, fate and functional significance of milk microRNAs. Importantly, recent studies have provided evidence of endogenous synthesis of HM microRNA within the human lactating mammary epithelium. These findings will now form the basis for investigations of the role of microRNA in the epigenetic control of normal and aberrant mammary development, and particularly lactation performance.

Challenges of deciphering gastric cancer heterogeneity

Gastric cancer is in decline in most developed countries; however, it still accounts for a notable fraction of global mortality and morbidity related to cancer. High-throughput methods are rapidly changing our view and understanding of the molecular basis of gastric carcinogenesis. Today, it is widely accepted that the molecular complexity and heterogeneity, both inter- and intra-tumour, of gastric adenocarcinomas present significant obstacles in elucidating specific biomarkers for early detection of the disease. Although genome-wide sequencing and gene expression studies have revealed the intricate nature of the molecular changes that occur in tumour landscapes, the collected data and results are complex and sometimes contradictory. Several aberrant molecules have already been tested in clinical trials, although their diagnostic and prognostic utilities have not been confirmed thus far. The gold standard for the detection of sporadic gastric cancer is still the gastric endoscopy, which is considered invasive. In addition, genome-wide association studies have confirmed that genetic variations are important contributors to increased cancer risk and could participate in the initiation of malignant transformation. This hypothesis could in part explain the late onset of sporadic gastric cancers. The elaborate interplay of polymorphic low penetrance genes and lifestyle and environmental risk factors requires additional research to decipher their relative impacts on tumorigenesis. The purpose of this article is to present details of the molecular heterogeneity of sporadic gastric cancers at the DNA, RNA, and proteome levels and to discuss issues relevant to the translation of basic research data to clinically valuable tools. The focus of this work is the identification of relevant molecular changes that could be detected non-invasively.

Associations of Polymorphisms in mir-196a2, mir-146a and mir-149 with Colorectal Cancer Risk: A Meta-Analysis

MicroRNAs (miRNAs) are non-coding RNAs which act as tumor suppressors or oncogenes. And single nucleotide polymorphism (SNP) in miRNA regions is one type of genetic variations in human genome. Various studies have investigated the associations of miRNAs SNP and kinds of cancers. In this article, we searched eligible studies to explore the relationships between mir-196a2 /mir-146a /mir-149 polymorphisms and colorectal cancer (CRC). A literature search of PubMed, Web of Science and ScienceDirect was conducted to identify all relevant studies. Three genetic models with pooled ratio and 95% confidence interval were used to evaluate the associations. We found that mir-196a2 polymorphism was significantly associated with CRC in Asian group (additive model: OR = 1.197, 95%CI 1.084 ~ 1.32, P < 0.001; dominant model: OR = 1.247, 95%CI 1.065 ~ 1.46, P = 0.006; recessive model: OR = 1.298, 95%CI 1.101 ~ 1.531, P = 0.002). And no associations were observed between SNPs of mir-146a, mir-149 and CRC in three genetic models. We also found CRC risk was not associated with mir-146a and mir-149 polymorphisms in population subgroup analysis. The current meta-analysis suggests that mir-196a2 polymorphism is associated with CRC, especially in Asian group. While, no associations have been found between mir-146a /mir-149 polymorphisms and CRC.

The polymorphic terminal-loop of pre-miR-1307 binding with MBNL1 contributes to colorectal carcinogenesis via interference with Dicer1 recruitment

Colorectal cancer (CRC) is one of the most common malignancies in the world. Studies have demonstrated that single nucleotide polymorphisms (SNPs) in microRNA genes (miRSNPs) are involved in the occurrence of cancers. However, the relationship between the miRSNPs within the terminal-loops of microRNA precursors and the development of CRC is still largely unknown. In this study, we found that a miRSNP rs7911488 T>C in the terminal-loop of pre-miR-1307 was significantly associated with the occurrence of CRC. The C allele of rs7911488 is more prevalent in CRC patients than in healthy controls (P < 0.001), and this C allele prevalence is related to low level of miR-1307 expression. A RNA-binding protein MBNL1 binds with a 'UGCUGC' motif in the terminal-loop of the C-allelic pre-miR-1307 and blocks Dicer processing, resulting in downregulation of miR-1307 expression. Consequently, the antiapoptosis protein Bcl2, which is a direct target of miR-1307, is overexpressed in CRC. Furthermore, MBNL1 participates in processing of both C-allelic and T-allelic pre-miR-1307. In summary, our results show that rs7911488 C-allelic pre-miR-1307 binds to MBNL1 and infers with Dicer processing, leading to reduced miR-1307 and increased Bcl2 expression, thus representing an important process in the initiation of CRC.

Cancer type-specific epigenetic changes: gastric cancer

Gastric cancer (GC) remains a major cause of mortality despite declining rate in the world. Epigenetic alterations contribute significantly to the development and progression of gastric tumors. Epigenetic refers to the number of modifications of the chromatin structure that affect gene expression without altering the primary sequence of DNA, and these changes lead to transcriptional activation or silencing of the gene. Over the years, the study of epigenetic processes has increased, and novel therapeutic approaches have emerged. This chapter summarizes the main epigenomic mechanisms described recently involved in gastric carcinogenesis, focusing on the roles that aberrant DNA methylation, histone modifications (histone acetylation and methylation), and miRNAs (oncogenic and tumor suppressor function of miRNA) play in the onset and progression of gastric tumors. Clinical implications of these epigenetic alterations in GC are also discussed.

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-605 represses PSMD10/Gankyrin and inhibits intrahepatic cholangiocarcinoma cell progression

The aberrant expression of PSMD10 has important functions in various malignancies. This study showed that PSMD10 was highly expressed and inversely correlated with the expression of miR-605 in intrahepatic cholangiocarcinoma (ICC) specimens. MiR-605 directly targeted and repressed PSMD10 expression. In addition, over-expression of miR-605 inhibited ICC cell progression both in vitro and in vivo. This effect of miR-605 on ICC cells was similar to that of PSMD10 knock-down by RNAi. Moreover, restoration of PSMD10 could reverse the phenotypic alteration caused by miR-605 in ICC cells. These results suggest a new therapeutic strategy in ICC by restoring miR-605, which is regulated by p53.

miRNA polymorphisms and risk of gastric cancer in Asian population

miRNAs are endogenous 19- to 25-nt noncoding RNAs that can negatively regulate gene expression by directly cleaving target mRNA or by inhibiting its translation. Recent studies have revealed that miRNA plays a significant role in gastric cancer development either as a tumor suppressor gene or oncogene. miRNA-single-nucleotide polymorphisms (SNPs), as a novel class of functional SNPs/polymorphisms, have been identified as candidate biomarkers for gastric cancer susceptibility. On the basis of recent data, the present review summarizes current knowledge of the functional effects of miRNA-SNPs and their importance as candidate gastric cancer biomarkers. Additionally, this review also includes a meta-analysis of the most frequently studied miRNA-SNPs in gastric cancer.

MicroRNA sequence polymorphisms and the risk of different types of cancer

MicroRNAs (miRNAs) participate in diverse biological pathways and may act as oncogenes or tumor suppressors. Single nucleotide polymorphisms (SNPs) in miRNAs (MirSNPs) might promote carcinogenesis by affecting miRNA function and/or maturation; however, the association between MirSNPs reported and cancer risk remain inconsistent. Here, we investigated the association between nine common MirSNPs and cancer risk using data from large scale case-control studies. Eight precursor-miRNA (pre-miRNA) SNPs (rs2043556/miR-605, rs3746444/miR-499a/b, rs4919510/miR-608, rs2910164/miR-146a, rs11614913/miR-196a2, rs895819/miR-27a, rs2292832/miR-149, rs6505162/miR-423) and one primary-miRNA (pri-miRNA) SNP (rs1834306/miR-100) were analyzed in 16399 cases and 21779 controls from seven published studies in eight common cancers. With a novel statistic, Cross phenotype meta-analysis (CPMA) of the association of MirSNPs with multiple phenotypes indicated rs2910164 C (P = 1.11E-03), rs2043556 C (P = 0.0165), rs6505162 C (P = 2.05E-03) and rs895819 (P = 0.0284) were associated with a significant overall risk of cancer. In conclusion, MirSNPs might affect an individual's susceptibility to various types of cancer.

The association between two microRNA variants (miR-499, miR-149) and gastrointestinal cancer risk: a meta-analysis

BACKGROUND

MicroRNAs (miRNAs) are small RNA molecules that regulate the expression of corresponding messenger RNAs (mRNAs). Single nucleotide polymorphisms (SNPs) in miRNAs may contribute to cancer susceptibility due to changes in the microRNA's properties and/or maturation. The present study aimed to investigate the association between two miRNA polymorphisms (miR-499 rs3746444 and miR-149 rs2292832) and gastrointestinal (GI) cancer risk.

METHODOLOGY/PRINCIPAL FINDINGS

We conducted a search of case-control studies in PubMed, Wiley Online Library, Web of Science and the CNKI database. Eleven rs3746444 studies and six rs2292832 studies were included in our meta-analysis. The only obvious association between the miR-499 polymorphism and colorectal cancer susceptibility was found in the homozygote comparison (GG vs. AA: OR = 1.66, 95% CI: 1.02-2.70, P(h) = 0.10, P = 0.04). No significant association was found in the subgroup analysis for ethnicity and risk of hepatocellular and gastric cancer. A marginally elevated GI cancer risk was discovered in the recessive model for miR-149 (TT vs. TC+CC: OR = 1.15, 95% CI: 1.03-1.30, P(h) = 0.68, P = 0.02). Stratifying the results by ethnicity revealed a slight association between the recessive model and the Asian population (TT vs. TC+CC: OR = 1.14, 95% CI: 1.01-1.29, P(h) = 0.79, P = 0.03).

CONCLUSIONS/SIGNIFICANCE

The present meta-analysis indicates that miR-499 may be associated with the risk to colorectal cancer. MiR-149 may confer a marginally increased risk of susceptibility to gastrointestinal cancer, especially for Asians.

Inferring the perturbed microRNA regulatory networks in cancer using hierarchical gene co-expression signatures

MicroRNAs (miRNAs), a class of endogenous small regulatory RNAs, play important roles in many biological and physiological processes. The perturbations of some miRNAs, which are usually called as onco-microRNAs (onco-miRs), are significantly associated with multiple stages of cancer. Although hundreds of miRNAs have been discovered, the perturbed miRNA regulatory networks and their functions are still poorly understood in cancer. Analyzing the expression patterns of miRNA target genes is a very useful strategy to infer the perturbed miRNA networks. However, due to the complexity of cancer transcriptome, current methods often encounter low sensitivity and report few onco-miR candidates. Here, we developed a new method, named miRHiC (enrichment analysis of miRNA targets in Hierarchical gene Co-expression signatures), to infer the perturbed miRNA regulatory networks by using the hierarchical co-expression signatures in large-scale cancer gene expression datasets. The method can infer onco-miR candidates and their target networks which are only linked to sub-clusters of the differentially expressed genes at fine scales of the co-expression hierarchy. On two real datasets of lung cancer and hepatocellular cancer, miRHiC uncovered several known onco-miRs and their target genes (such as miR-26, miR-29, miR-124, miR-125 and miR-200) and also identified many new candidates (such as miR-149, which is inferred in both types of cancers). Using hierarchical gene co-expression signatures, miRHiC can greatly increase the sensitivity for inferring the perturbed miRNA regulatory networks in cancer. All Perl scripts of miRHiC and the detailed documents are freely available on the web at http://bioinfo.au.tsinghua.edu.cn/member/jgu/miRHiC/.

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.

Lack of association between hsa-miR-149 rs2292832 polymorphism and cancer risk: a meta-analysis of 12 studies

BACKGROUND

MicroRNAs (miRNAs) participate in various cellular processes such as cell growth, differentiation, cell death and play an important role in a variety of diseases, especially in cancer. Recently, a number of studies have investigated the association between single nucleotide polymorphisms (SNPs) on the hsa-miR-149 rs2292832 and susceptibility to cancer; however, the results remain inconclusive.

METHODOLOGY/PRINCIPAL FINDINGS

We carried out a meta-analysis of 12 studies including 5937 cases and 6081 controls from PubMed to assess the association between the hsa-miR-149 rs2292832 and cancer risk by pooled odds ratios (ORs) and 95% confidence intervals (CIs). However, our results showed that genotype distribution of the hsa-miR-149 rs2292832 was not associated with cancer risk in all genetic models. Subgroup analysis by cancer type, ethnicity or study design showed no significant association either.

CONCLUSION

Results of this meta-analysis suggest that the hsa-miR-149 rs2292832 polymorphism is not associated with cancer risk in spite of the potentially protective role of C allele in hepatocellular carcinoma and male gastric cancer.

A pre-microRNA-149 (miR-149) genetic variation affects miR-149 maturation and its ability to regulate the Puma protein in apoptosis

MicroRNAs (miRNAs) are small, single-stranded, noncoding RNAs that function as negative regulators of gene expression. They are transcribed from endogenous DNA and form hairpin structures (termed as pre-miRNAs) that are processed to form mature miRNAs. It remains largely unknown as to the molecular consequences of the natural genetic variation in pre-miRNAs. Here, we report that an A→G polymorphism (rs71428439) is located in Homo sapiens miR-149 stem-loop region. This polymorphism results in a change in the structure of the miR-149 precursor. Our results showed that the genotype distribution of this polymorphism in myocardial infarction cases was significantly different from that in the control subjects. We examined the biological significance of this polymorphism on the production of mature miR-149, and we observed that the G-allelic miR-149 precursor displayed a lower production of mature miR-149 compared with the A-allelic one. Further investigations disclosed that miR-149 could withstand mitochondrial fission and apoptosis through targeting the pro-apoptotic factor p53-up-regulated modulator of apoptosis (Puma). Enforced expression of miR-149 promoted cell survival, whereas knockdown of miR-149 rendered cells to be sensitive to apoptotic stimulation. Intriguingly, the A to G variation led pre-miR-149 to elicit an attenuated effect on the inhibition of mitochondrial fission and apoptosis. Finally, this polymorphism exerts its influence on cardiac function in the mouse model of myocardial infarction. These data suggest that this polymorphism in the miR-149 precursor may result in important phenotypic traits of myocardial infarction. Our findings warrant further investigations on the relationship between miR-149 polymorphism and myocardial infarction.

Association study between miR-149 gene polymorphism and nasopharyngeal carcinoma

Association studies between single-nucleotide polymorphism (SNP) rs2292832 on miR-149 gene and cancer risk have been previously analyzed in several types of cancer. The aim of this study was to evaluate the association between miR-149 polymorphism and risk of nasopharyngeal carcinoma (NPC). miR-149 gene polymorphism was genotyped using polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) in 158 patients with NPC and 242 healthy individuals. Associations with cancer risk and clinicopathological characteristics were analyzed by χ² test. No significant difference was observed for miR-149 gene polymorphism in NPC patients and healthy controls in either genotype (P=0.427 for CC vs. CT vs. TT, P=0.247 for CT vs. TT and P=0.323 for CC vs. TT, respectively) or allelic analysis (P=0.216). No significant difference was noted between the genotypes and the clinicopathological parameters examined with the exception of clinical stage. A significantly higher CC distribution in clinical stage I-II compared with III-IV was observed under the dominant model (CC vs. CT vs. TT, P=0.026) and the co-dominant model (CC vs. TT, P=0.030). The results of this study suggested that the CC genotype of miR-149 contributes to the progression and development, rather than the initiation of NPC.

The association between genetic polymorphism and the processing efficiency of miR-149 affects the prognosis of patients with head and neck squamous cell carcinoma

MicroRNAs (miRNAs) play important roles in modulating the neoplastic process of cancers including head and neck squamous cell carcinoma (HNSCC). A genetic polymorphism (rs2292832, C>T) has been recently identified in the precursor of miR-149; nevertheless its clinicopathological implications remain obscure. In this study, we showed that miR-149 is down-regulated in HNSCC compared to normal mucosa and this is associated with a poorer patient survival. In addition, HNSCC patients with the T/T genotype have more advanced tumors and a worse prognosis. Multivariate analysis indicated that patients carried the T/T genotype have a 2.81-fold (95% CI: 1.58–4.97) increased risk of nodal metastasis and 1.66-fold (95% CI: 1.05–2.60) increased risk of mortality compared to other groups. T/T genotype also predicted the worse prognosis of buccal mucosa carcinoma subset of HNSCC. In vitro analysis indicated that exogenous miR-149 expression reduces the migration of HNSCC cells. Moreover, HNSCC cell subclones carrying the pri-mir-149 sequence containing the T variant show a low processing efficacy when converting the pre-mir-149 to mature miR-149. These findings suggest that miR-149 suppresses tumor cell mobility, and that the pre-mir-149 polymorphism may affect the processing of miR-149, resulting in a change in the abundance of the mature form miRNA, which, in turn, modulates tumor progression and patient survival.

Advances in understanding relationship between miRNA single nucleotide polymorphisms and colorectal cancer

The occurrence and development of colorectal cancer (CRC) are a multifactorial, multi-step evolutionary process. Gene polymorphisms are often involved in tumor development and prognosis. Recent studies have found that certain microRNA (miRNA) single nucleotide polymorphisms were associated with genetic susceptibility to and prognosis of CRC. Understanding the relationship between miRNA single nucleotide polymorphisms and CRC can provide new clues to the detection, prevention, and prognostic evaluation of CRC.

Microrna-149 Inhibits Proliferation and Invasion of Glioma Cells via Blockade of Akt1 Signaling

MicroRNAs (miRNAs) play important roles in the regulation of gene expressions. Aberrant expression of miRNAs is implicated in a variety of biological and pathological processes, including the tumorigenesis of glioma (GM). Though the molecular mechanisms of protein kinase B (AKT) survival signal have been comprehensively explored, the role of miR-149 in glioblastoma (GBM) and its regulation on AKT signaling have not yet been ascertained. The present study aimed to elucidate the role and molecular mechanisms of miR-149 in U251 GM cells. Using a gain-of-function approach, we investigated the effects of lentivirus-mediated overexpression of miR-149 on the expression of phosphated-AKT1 (p-AKT1), proliferating cell nuclear antigen (PCNA), matrix metallopeptidase-2 (MMP-2) and CyclinD1 in U251 cells and nude mice subcutaneous xenograft tumors by Real-time PCR, Western blot and immunohistochemical assays. Proliferative activities indicated by MTT assay, invasive potential by Transwell and cycle distribution by flow cytometry were carried out for functional analysis of U251 cells after infection with miR-149 mimic. As a consequence, miR-149 inhibited the expression of p-AKT1, PCNA, CyclinD1 and MMP-2, reduced the proliferative activities and invasive potential, and induced cycle arrest in G0/G1 phase in U251 cells. In conclusion, our findings show that miR-149 as tumor suppressor may be involved in the proliferation and invasion of GM cells via blockade of the AKT1 signaling, and be considered as a candidate target for the treatment of cancer.

Association of the miR-146aC>G, miR-149T>C, miR-196a2T>C, and miR-499A>G polymorphisms with gastric cancer risk and survival in the Korean population

We investigated whether four common microRNA polymorphisms (miR-146aC>G [rs2910164], miR-149T>C [rs2292832], miR-196a2T>C [rs11614913], and miR-499A>G [rs3746444]) are associated with the susceptibility and prognosis of gastric cancer in the Korean population. The four microRNA single-nucleotide polymorphisms (SNPs) were identified in a case-control study (461 patients; 447 controls) by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis in the Korean population. When patients were stratified into diffuse and intestinal-type gastric cancer groups, subjects with the miR-499AG and AG + GG genotypes had reduced adjusted odds ratios (AORs) for diffuse-type gastric cancer (AOR = 0.54 with 95% confidence interval [CI] = 0.31-0.97; AOR = 0.57 with 95% CI = 0.33-0.97). In the stratified analyses for gastric cancer risk, the miR-146aGG and CG + GG genotypes were associated with increased risk of gastric cancers among the non-smokers, whereas the miR-149TC and TC + CC genotypes showed lower risk of gastric cancer in males. The miR-196a2CC genotype was associated with elevated gastric cancer risk among females. For gastric cancer prognosis, intestinal-type gastric cancer patients with miR-146aCG + GG genotypes had significantly higher survival rates (log-rank P = 0.030) than patients with the CC genotype, and patients with the miR-499AA genotype had significantly increased survival rates compared to patients with the AG + GG genotypes (log-rank P = 0.013). When miR-146aCG + GG and miR-499AA genotypes were combined, the survival rate of intestinal-type gastric cancer patients was elevated (log-rank P < 0.001). No association was found between gastric or diffuse-type cancer prognosis and other miRNAs. Our data demonstrate that specific miRNA SNPs are associated with gastric cancer susceptibility (miR-499A>G) and prognosis (miR-146aC>G and miR-499A>G) in the Korean population depending on gastric cancer type.

Lack of association between miR-149 C>T polymorphism and cancer susceptibility: a meta-analysis based on 4,677 cases and 4,830 controls

To derive a more precise estimation of the relationship between miR-149 C>T polymorphism and cancer risk, a meta-analysis was performed. A total of 8 studies including 4,677 cases and 4,830 controls were involved in this meta-analysis. Overall, no significantly elevated cancer risk was associated with miR-149 T allele when all studies were pooled into the meta-analysis (CT vs. CC: OR = 0.977, 95 % CI = 0.882-1.082; TT vs. CC: OR = 0.985, 95 % CI = 0.857-1.132; dominant model: OR = 0.984, 95 % CI = 0.893-1.084; recessive model: OR = 1.026, 95 % CI = 0.931-1.132). In the subgroup analysis by ethnicity or study design, no significantly increased risks were found under all models. When stratified by cancer type, there were no significant cancer risk changes for lung cancer, breast cancer or colorectal cancer when miR-149 T allele was included. In conclusion, this meta-analysis suggests that the miR-149 C>T polymorphism may not contribute to cancer susceptibility.