Suppression of Wnt/ß-catenin Signaling in PDAC via METTL16-mediated N6-methyladenosine Modification of DVL2.

Pancreatic cancer is a formidable cause of cancer-related deaths worldwide and has witnessed a more than twofold increase in incidence over the last 25 years. The most frequently occurring form of pancreatic cancer is pancreatic ductal adenocarcinoma (PDAC), accounting for the majority of pancreatic cancer cases. N6-methyladenosine (m6A), the most abundant transcript modification, has been implicated in the pathogenesis of numerous human cancers, including pancreatic cancer. Despite this, the functional role of methyltransferase-like 16 (METTL16), a critical m6A methyltransferase, in PDAC remains elusive. In this study, we demonstrate that METTL16 expression is significantly diminished in PDAC, rendering it a promising prognostic indicator. Strikingly, both in vitro and in vivo assays revealed accelerated metastasis and invasion of PDAC cells upon METTL16 knockdown, while overexpression of METTL16 exerted an opposite effect. Mechanistically, METTL16 regulates DVL2 expression by suppressing its translation via m6A modification, thereby regulating Wnt/ß-catenin signaling., Our results unveil the downregulation of METTL16 as a concomitant increase in DVL2 levels via m6A modification promoting the progression of PDAC. Thus, we propose METTL16 as a novel therapeutic candidate for targeted PDAC treatment.

Identification of m7G-Related LncRNA Signature for Predicting Prognosis and Evaluating Tumor Immune Infiltration in Pancreatic Adenocarcinoma.

N7-Methylguanosine (m7G) modification holds significant importance in regulating posttranscriptional gene expression in epigenetics. Long non-coding RNAs (lncRNAs) have been demonstrated to play a crucial role in cancer progression. m7G-related lncRNA may be involved in the progression of pancreatic cancer (PC), although the underlying mechanism of regulation remains obscure. We obtained RNA sequence transcriptome data and relevant clinical information from the TCGA and GTEx databases. Univariate and multivariate Cox proportional risk analyses were performed to build a twelve-m7G-associated lncRNA risk model with prognostic value. The model was verified using receiver operating characteristic curve analysis and Kaplan-Meier analysis. The expression level of m7G-related lncRNAs in vitro was validated. Knockdown of SNHG8 increased the proliferation and migration of PC cells. Differentially expressed genes between high- and low-risk groups were identified for gene set enrichment analysis, immune infiltration, and potential drug exploration. We conducted an m7G-related lncRNA predictive risk model for PC patients. The model had independent prognostic significance and offered an exact survival prediction. The research provided us with better knowledge of the regulation of tumor-infiltrating lymphocytes in PC. The m7G-related lncRNA risk model may serve as a precise prognostic tool and indicate prospective therapeutic targets for PC patients.

METTL14 Facilitates the Metastasis of Pancreatic Carcinoma by Stabilizing LINC00941 in an m6A-IGF2BP2-Dependent Manner.

Pancreatic adenocarcinoma (PC), one of the most fatal diseases, usually generates a poor prognosis in advanced stages. N6-methyladenosine modification has emerged as a crucial participant in tumor development and recurrence. Methyltransferase-like 14 (METTL14), as a core member of methyltransferases, is involved in tumor progression and metastasis. However, the potential mechanism by which METTL14 regulates long noncoding RNAs (lncRNAs) in PC remains unclear. RNA immunoprecipitation (RIP), methylated RNA immunoprecipitation quantitative PCR (MeRIP-qPCR), and fluorescence in situ hybridization (FISH) were used to explore the underlying mechanisms. In our study, we found that METTL14 expression was upregulated in PC patients, and was associated with poor prognosis. In vitro and in vivo experiments, knocking down METTL14 suppressed tumor metastasis. RNA-seq and bioinformatics analyses were used to identify LINC00941 as the downstream target of METTL14. Mechanistically, LINC00941 was upregulated by METTL14 in an m6A-dependent way. LINC00941 was recruited and recognized by IGF2BP2. METTL14 enhanced the affinity of IGF2BP2 for LINC00941, while IGF2BP2 promoted the stabilization of LINC00941, which contributed to the migration and invasion of PC cells. Overall, our research revealed that METTL14 promoted the metastasis of PC through m6A modification of LINC00941. Targeting the METTL14-LINC00941-IGF2BP2 axis may provide promising therapeutic approaches for PC.

The Wet Suction Technique Enhances the Diagnostic Efficacy and Aspirate Quality of EUS-FNA for Solid Lesions: A Multicenter Retrospective Study in China.

GOALS: To comprehensively compare the wet suction technique with the conventional dry suction technique for endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in solid lesions. BACKGROUND: Optimal suction techniques for EUS-FNA remain uncertain when approaching solid lesions. STUDY: We performed a retrospective study of EUS-FNA at 3 medical centers in China. A total of 203 patients were enrolled who received 2 passes of EUS-FNA with 22-G needles. If the first pass underwent dry suction, the second pass was wet suction. Otherwise, the order of suction technique is opposite. Diagnostic accuracy, sample quality (including cellularity and blood contamination), and sample quantity (including specimen adequacy, the maximum intact specimen length, and the total specimen length) were compared between wet-suction and dry-suction techniques. RESULTS: The patients included 143 pancreatic lesions and 60 nonpancreatic lesions. Compared with the dry suction technique, the wet suction technique yielded a significantly higher diagnostic accuracy (85.22% vs. 72.41%, P =0.002), better specimen adequacy score and cellularity score ( P <0.0001), and lower blood contamination score ( P <0.0001). In the subgroup analysis, wet suction provided significantly higher diagnostic accuracy in pancreatic cancer without chronic pancreatitis ( P <0.05), and better cellularity score and specimen adequacy score, lower blood contamination score, and longer maximum intact specimen length and total specimen length in various lesions than that in dry suction. CONCLUSIONS: The wet suction technique resulted in significantly higher diagnostic accuracy in pancreatic cancer without chronic pancreatitis, and better cellularity and histologic specimen in most of solid lesions.

Transpapillary Stenting Improves Treatment Outcomes in Patients Undergoing Endoscopic Transmural Drainage of Ductal Disruption-Associated Pancreatic Fluid Collections.

INTRODUCTION: Endoscopic transmural drainage (TMD) has been accepted as the preferred therapy for symptomatic pancreatic fluid collections (PFCs). Recurrence of PFCs presents a unique challenge in patients with disrupted pancreatic duct (PD). We aimed to evaluate whether transpapillary drainage (TPD) provides additional benefits to TMD in patients with PD disruption. METHODS: This was a multicenter retrospective study. Consecutive patients who underwent TMD, TPD, or combined drainage (CD) of PFCs were included. The primary outcome was to compare PFC recurrence among different groups. The secondary outcomes were the technical success rate, length of hospital stay, and procedure-related complications. RESULTS: A total of 153 patients, which consists of 57 patients with pancreatic pseudocysts and 96 patients with walled-off necrosis, were included. PFC recurrence was more common in patients with PD disruption than those with an intact main duct (19% vs 1.4%, P < 0.001). PD disruption was identified as a major risk factor of PFC recurrence by univariable and multivariable analyses. The recurrence rate of CD was significantly lower than TMD only or TPD only (6.5% vs 15.4% vs 22.7%, P < 0.01). The length of hospital stay of CD was significantly shorter than TMD only or TPD only (5 [3.0-9.0] vs 7.0 [5.0-12.0] vs 9 [7.0-16.0], P < 0.001). Dual-modality drainage did not increase procedure-related complications compared with TMD only (13.0% vs 12.8%, P > 0.05). Partial PD disruption was bridged in 87.3% cases while complete PD disruption was reconnected in 55.2% cases. Although statistically not significant, the clinical success rate in walled-off necrosis cases with actively bridged ducts was much higher than those with passively bridged ducts (76.9% vs 40%). DISCUSSION: Transpapillary pancreatic duct stenting seems to improve the efficacy of endoscopic TMD of pancreatic duct disruption-associated PFCs by reducing the recurrence rate and shortening the length of hospital stay.

Preoperative Extrapancreatic Extension Prediction in Patients with Pancreatic Cancer Using Multiparameter MRI and Machine Learning-Based Radiomics Model.

RATIONALE AND OBJECTIVES: Pancreatic cancer is a common malignant tumor with a dismal prognosis. Preoperative differentiation of extrapancreatic extension (EPE) based on radiomics will facilitate treatment decision-making. MATERIALS AND METHODS: This research retrospectively recruited 156 patients from two medical centers. 122 patients from the center A were randomly divided into the training set and the internal test set in a 4:1 ratio. Additionally, 34 patients from the center B served as the external test set. Radiomics features were extracted from multiparametric MRI (MP-MRI), containing axial T2 weighted imaging (T2WI), diffusion weighted imaging (DWI), and dynamic contrast enhancement (DCE) sequences. The three-step method was used for feature extraction: SelecteKBest, least absolute shrinkage and selection operator (LASSO) algorithm, and recursive feature elimination based on random forest (RFE-RF). The model was constructed using six classifiers based on machine learning, and the classifier with the best performance was chosen. Finally, clinical factors associated with EPE were incorporated into the combined model. RESULTS: The classifier with the best performance was XGBoost, which obtained area under curve (AUC) values of 0.853 and 0.848 in the internal and external test sets, respectively. Through SelectKBest, the most relevant clinical factor for EPE was determined to be platelet, which was then added to the combined model, yielding AUC values of 0.880 and 0.848 in the internal and external test sets, respectively. CONCLUSION: Radiomics models had the potential to noninvasively and accurately predict EPE before surgery. Additionally, it would add value to personalized precision treatment.

Identification and Validation of Prognostic Model for Pancreatic Ductal Adenocarcinoma Based on Necroptosis-Related Genes.

Background: Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant tumors with a poor prognosis. Recently, necroptosis has been reported to participate in the progression of multiple tumors. However, few studies have revealed the relationship between necroptosis and PDAC, and the role of necroptosis in PDAC has not yet been clarified. Methods: The mRNA expression data and corresponding clinical information of PDAC patients were downloaded from the TCGA and GEO databases. The necroptosis-related genes (NRGs) were obtained from the CUSABIO website. Consensus clustering was performed to divide PDAC patients into two clusters. Univariate and LASSO Cox regression analyses were applied to screen the NRGs related to prognosis to construct the prognostic model. The predictive value of the prognostic model was evaluated by Kaplan-Meier survival analysis and ROC curve. Univariate and multivariate Cox regression analyses were used to evaluate whether the risk score could be used as an independent predictor of PDAC prognosis. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and single-sample gene set enrichment analysis (ssGSEA) were used for functional enrichment analysis. Finally, using qRT-PCR examined NRGs mRNA expression in vitro. Results: Based on the TCGA database, a total of 22 differential expressed NRGs were identified, among which eight NRGs (CAPN2, CHMP4C, PLA2G4F, PYGB, BCL2, JAK3, PLA2G4C and STAT4) that may be related to prognosis were screened by univariate Cox regression analysis. And CAPN2, CHMP4C, PLA2G4C and STAT4 were further selected to construct the prognostic model. Kaplan-Meier survival analysis and ROC curve showed that there was a significant correlation between the risk model and prognosis. Univariate and multivariate Cox regression analyses showed that the risk score of the prognostic model could be used as an independent predictor. The model efficacy was further demonstrated in the GEO cohort. Functional analysis revealed that there were significant differences in immune status between high and low-risk groups. Finally, the qRT-PCR results revealed a similar dysregulation of NRGs in PDAC cell lines. Conclusion: This study successfully constructed and verified a prognostic model based on NRGs, which has a good predictive value for the prognosis of PDAC patients.

RELA-induced MiR-21 Exerts Oncogenic Effects on PDAC via Targeting of ARHGAP24.

Inflammation is one of the inducing factors of pancreatic ductal adenocarcinoma (PDAC), and microRNAs have been confirmed to be involved in the occurrence and development of PDAC. However, whether RELA, an inflammatory regulator, is involved in the regulation of PDAC by miRNA remains to be further studied. In the present study miR-21 was characterized and its upstream regulatory mechanism was investigated, as well as its functional effects and target genes in pancreatic ductal adenocarcinoma (PDAC). In situ hybridization analysis confirmed increased miR-21 expression levels in PDAC tissues. The results of the chromatin immunoprecipitation and dual-luciferase reporter assays demonstrated that transcription factor RELA modulated miR-21 transcription in the PDAC, PANC-1 and MIA PaCa-2 cell lines. Subsequently, a cell viability assay, EdU staining assay and flow cytometry analysis, demonstrated that miR-21 promoted cell proliferation and cell cycle progression, but inhibited cell apoptosis in vitro. Furthermore, a xenograft assay demonstrated that miR-21 accelerated tumor growth in vivo. Mechanistically, miR-21 directly regulated the expression of Rho GTPase activating protein 24 (ARHGAP24), which was indicated to be a tumor suppressor gene. Moreover, both miR-21 and ARHGAP24 were strongly associated with clinical features and may therefore serve as valuable biomarkers in PDAC prognosis.

Circular RNA circ_0047744 suppresses the metastasis of pancreatic ductal adenocarcinoma by regulating the miR-21/SOCS5 axis.

There is increasing evidence that circular RNAs (circRNAs) can serve as microRNA (miRNA) sponges to regulate metastasis of multiple tumors, including pancreatic ductal adenocarcinoma (PDAC). However, the role of the circRNA/miRNA regulatory network in metastasis of PDAC has not been elucidated. The purpose of this study is to explore the role of circ_0047744/miR-21/SOCS5 in the metastasis of PDAC. We found that circRNA_0047744 was weakly expressed in PDAC tissues and cell lines. The expression of circ_0047744 was negatively correlated with lymph node metastasis and positively correlated with overall survival in PDAC patients. Functionally, the overexpression of circ_0047744 suppressed cell migration and invasion in vitro and in vivo. Mechanistically, circ_0047744 could regulate SOCS5 expression by acting as a sponge of miR-21 to inhibit migration and invasion of PDAC cells. Our study demonstrates that circ_0047744 acts as an anti-oncogene to inhibit PDAC metastasis by regulating the miR-21/SOCS5 axis, indicating that circ_0047744 may be a potential novel therapeutic target for PDAC patients.

MiR-556-5p modulates migration, invasion, and epithelial-mesenchymal transition in breast cancer cells via targeting PTHrP.

Breast cancer bone metastases may block normal bone remodeling and promote bone degradation, during which several signaling pathways and small non-coding miRNAs might all play a role. miRNAs and target mRNAs that might be associated with breast cancer bone metastasis were analyzed and selected using bioinformatics analyses based on online data. The 3' untranslated region of key factors associated with breast cancer metastasis were examined for candidate miRNA binding site using Targetscan. The predicted binding was validated. The specific effects of single miRNA and dynamic effects of the miRNA-mRNA axis on breast cancer cell metastasis were investigated. miR-556-5p was downregulated in breast cancer samples according to online datasets and experimental analyses. In breast cancer cells, miR-556-5p overexpression inhibited, whereas miR-556-5p inhibition promoted cancer cell invasion and migration. Among key factors associated with breast cancer bone metastasis, parathyroid hormone related protein (PTHrP) 3'UTR possessed miR-556-5p binding site. Through direct binding, miR-556-5p negatively regulated PTHrP expression. In breast cancer cell lines, miR-556-5p inhibition promoted, whereas PTHrP silencing suppressed cancer cell migration, invasion, and epithelial-mesenchymal transition; the effects of miR-556-5p inhibition were partially reversed by PTHrP silencing. In summary, miR-556-5p targets PTHrP to modulate the cell migration and invasion of breast cancer.

ELK3 Mediated by ZEB1 Facilitates the Growth and Metastasis of Pancreatic Carcinoma by Activating the Wnt/ß-Catenin Pathway.

Rapid progression and metastasis are the major causes of death in patients with pancreatic ductal adenocarcinoma (PDAC). ELK3, a member of the ternary complex factor (TCF), has been associated with the initiation and progression of various cancers. However, the role of ELK3 in PDAC is not yet fully understood. Online databases and immunohistochemistry were used to analyze the ELK3 levels in PDAC tissues. The function of ELK3 was confirmed by a series of in vivo and in vitro studies. Western blotting and immunofluorescence were used to detect the molecular mechanisms of PDAC. ChIP-qPCR was used to study the mechanism responsible for the elevation of ELK3 expression in PDAC. The ELK3 levels were higher in PDAC tissues than in adjacent normal tissues. Functionally, we demonstrated that ELK3 acted as an oncogene to promote PDAC tumorigenesis and metastasis. Further study suggested that ELK3 promoted PDAC cell migration and invasion by activating the Wnt/ß-catenin pathway, and proved that ZEB1 could directly bind to the promoter of ELK3 to increase its transcription. Finally, both were associated with the patients' clinicopathological features and worse overall survival. Conclusively, our findings enrich the role of ELK3 in PDAC, and provide potential avenues for exploring more effective biomarkers and therapeutic strategies for the treatment of PDAC.

Biodegradable JDBM coating stent has potential to be used in the treatment of benign biliary strictures.

In our previous study, to find out the optimal alloy suitable for biliary surgery, magnesium alloy Jiao Da Bio-magnesium (denoted as JDBM) alloy, Zn-3Cu alloys, and their respective coating (MgF2-PDLLA) products were produced for our research. We found that JDBM seems to be a potential material for clinical biliary stent application due to its uniform degradation and good compatibility. In order to apply the JDBM alloy to treat benign bile duct stricture, our group prepared the bare JDBM and its coating product into finished stents by mesh weaving carving technology and conducted the mechanical property tests, degradation tests and biocompatibility tests. During the mechanical property tests, we found the bare JDBM stent was more suitable than titanium alloy stent when applies to the bile duct, and the coating of the JDBM coating stent has no effect on its mechanical properties. Our in vitro and in vivo experiments revealed that the degradation rate of the JDBM coating stent is lower than that of the JDBM stent, and both stents were biosafe. Thus, there is promise for JDBM coating stents for the treatment of benign biliary strictures.

Comparative assessment of the biocompatibility and degradation behavior of Zn-3Cu and JDBM alloys used for biliary surgery.

This study was designed to investigate the biocompatibility and the degradation behavior of a Zn-3Cu alloy, a Zn-3Cu coating alloy, a Mg-Nd-Zn-Zr (denoted as JDBM) alloy and a JDBM coating alloy to choose the optimal alloy for common bile duct (CBD) surgery. In the in vitro degradation experiments, we observed the surface morphology of the samples and determined the elements of the corrosion products. In the in vitro cytotoxicity experiments, the cell morphology and cytotoxicity were observed and tested. In the in vivo experiments, in addition to analyzing the samples, we also analyzed the variations in serum magnesium, serum creatinine (CREA), blood urea nitrogen (BUN), total bilirubin (TB) and glutamic pyruvic transaminase (GPT). Moreover, important tissue samples from the CBD, liver, kidney and spleen were taken for histological evaluation. The in vitro degradation experiments revealed that the surface corrosion of the JDBM and JDBM coating alloys were more obvious than that of Zn-3Cu and Zn-3Cu coating alloys, and the degradation rate of the JDBM coating alloy was the slowest. The in vitro cytotoxicity assessment showed that the JDBM alloy and JDBM coating alloy extracts were biologically safe for L-929 cells, while the Zn-3Cu alloy and Zn-3Cu coating alloy extracts were harmful to L-929 cells. In the in vivo experiments, neither the JDBM alloy nor the JDBM coating alloy affected the function or morphology of the bile duct, liver, kidney or spleen. Similar to the in vitro degradation behavior, the surface corrosion of the JDBM alloy was more significant than that of the JDBM coating alloy. Our data suggested that the JDBM coating alloy is a safe, biodegradable material for CBD surgery.

Modified Mahalanobis-Taguchi System based on proper orthogonal decomposition for high-dimensional-small-sample-size data classification.

Mahalanobis-Taguchi System (MTS) is an effective algorithm for dimensionality reduction, feature extraction and classification of data in a multidimensional system. However, when applied to the field of high-dimensional small sample data, MTS has challenges in calculating the Mahalanobis distance due to the singularity of the covariance matrix. To this end, we construct a modified Mahalanobis-Taguchi System (MMTS) by introducing the idea of proper orthogonal decomposition (POD). The constructed MMTS expands the application scope of MTS, taking into account correlations between variables and the influence of dimensionality. It can not only retain most of the original sample information features, but also achieve a substantial reduction in dimensionality, showing excellent classification performance. The results show that, compared with expert classification, individual classifiers such as NB, RF, k-NN, SVM and superimposed classifiers such as Wrapper + RF, MRMR + SVM, Chi-square + BP, SMOTE + Wrapper + RF and SMOTE + MRMR + SVM, MMTS has a better classification performance when extracting orthogonal decomposition vectors with eigenvalues greater than 0.001.

Spautin-A41 Attenuates Cerulein-Induced Acute Pancreatitis through Inhibition of Dysregulated Autophagy.

Autophagy plays key roles in the development of acute pancreatitis (AP) and the regulation of impaired autophagy has therapeutic potential. The objective of the present study was to investigate whether pharmacological inhibition of autophagy could ameliorate AP in mice and examine the underlying mechanisms. In current study, by imaging-based high-throughput screening, a novel spautin-1 derivative spautin-A41 was identified as a potent autophagy inhibitor. Mice treated with spautin-A41 were resistant to the cerulein-induced elevation of serum pancreatic enzyme activities and pancreatic apoptosis. Mechanistically, spautin-A41 effectively reduced the expression levels of Class III phosphatidylinositol 3 (PI3) kinase complexes and subsequently ameliorated pancreatitis by inhibiting the formation of autophagosome. Therefore, pharmacological inhibition of autophagy by spautin-A41 may serve as new target for treating or lessening the severity of AP.

miR-21 promotes EGF-induced pancreatic cancer cell proliferation by targeting Spry2.

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant cancer that lacks effective targets for therapy. Alteration of epidermal growth factor (EGF) expression has been recognized as an essential molecular event in pancreatic carcinogenesis. Accumulating studies have demonstrated that miRNAs play critical roles in EGF signaling regulation, tumor initiation, cell proliferation and apoptosis. Here, we demonstrated that miR-21 expression was induced by EGF in pancreatic cancer cells. miR-21 promoted EGF-induced proliferation, inhibited cell apoptosis and accelerated cell cycle progression. In vivo experiments confirmed the influence of miR-21 on tumor growth. Mechanistic studies revealed that miR-21 targeted MAPK/ERK and PI3K/AKT signaling pathways to modulate cell proliferation. In addition, Spry2 was proven to be a target of miR-21. Furthermore, miR-21 and Spry2 were significantly related to clinical features and may be valuable predictors of PDAC patient prognosis.

The efficacy of temporary placement of nasobiliary drainage following endoscopic metal stenting to prevent post-ERCP cholangitis in patients with cholangiocarcinoma.

BACKGROUND/AIMS: Although endoscopic metal biliary endoprosthesis (EMBE) is widely accepted as the most suitable drainage method for patients with unresectable malignant obstruction, uncontrolled post-procedural cholangitis is still a problem. We aimed to validate a new treatment modality to prevent post-ERCP cholangitis in patients with unresectable cholangiocarcinoma. PATIENTS AND METHODS: A total of 378 patients who were diagnosed with unresectable malignant biliary obstruction and underwent EMBE or temporary endoscopic nasobiliary drainage (ENBD) following EMBE placement, from January 2010 to July 2016, were enrolled in this retrospective study. Incidence of cholangitis, related infectious indicators, success rate of biliary drainage, and occurrence of complications were evaluated. RESULTS: The risk of overall cholangitis and related infectious indicators was significantly lower in EMBE plus ENBD group than that in EMBE group. The occurrence of cholangitis was 2.4% versus 11.9% (P = 0.004). On further analysis of subgroups, although no difference was detected in nonhilar cholangiocarcinoma subgroup, the incidence of cholangitis and related infectious indicators in hilar cholangiocarcinoma subgroup with EMBE modality were distinctly higher than that with EMBE plus ENBD modality (type I + II was 18.5% vs 0%, P < 0.05; type III + IV was 19.8% vs 3.8%, P < 0.05). No significant difference was found in successful biliary drainage rate and procedure-related complications when all subgroups were compared. CONCLUSIONS: The temporary placement of ENBD following EMBE is a simple and effective treatment modality to prevent post-ERCP cholangitis, especially in patients with hilar cholangiocarcinoma.

Dietary vitamin B2 intake and breast cancer risk: a systematic review and meta-analysis.

BACKGROUND: Epidemiological studies assessing the relationship between dietary vitamin B2 and the risk of breast cancer have produced inconsistent results. Thus, we conducted this meta-analysis of epidemiologic studies to evaluate this association. METHODS: We searched English-language MEDLINE publications and conducted a manual search to screen eligible articles. A random-effect model was used to pool study-specific risk estimates. Egger's linear regression test was also used to detect publication bias in meta-analysis. RESULTS: In our meta-analysis, ten studies comprising totally 12,268 breast cancer patients were available in the analyses. Pooled relative risk (RR) comparing the highest to the lowest vitamin B2 intake and breast cancer incidence was 0.85 [95% confidence interval (CI) = 0.76-0.95]. No significant heterogeneity existed across the studies (P = 0.086, I 2 = 40.7%). No publication bias was found. The results of dose-response analysis also showed that an increment of 1 mg/day was inversely related to the risk of breast cancer (RR = 0.94; 95% CI = 0.90-0.99). CONCLUSIONS: Results from our meta-analysis indicated that dietary vitamin B2 intake is weakly related to the reduced risk of breast cancer. Additional research is also necessary to further explore this association.