Increased LACTB2 Expression Regulates Oxidative Phosphorylation and mTORC1 Signaling of Colorectal Cancer.

This study aimed to investigate the mechanisms of LACTB2 in colorectal cancer (CRC). Microarrays and sequencing data of CRC were acquired from UCSC Xena, GTEx, Gene Expression Omnibus, and TCGA. Pooled analysis of the mRNA expression of LACTB2 in CRC was performed using Stata software. The protein expression of LACTB2 in CRC tissues was evaluated by immunohistochemistry. The relationship between immune cell infiltration and LACTB2 expression was investigated using CIBERSORT. The potential signaling pathways and biological mechanisms of LACTB2 were explored using GSEA, KEGG, and GO. Subsequently, further screening of small molecular compounds with potential therapeutic effects on CRC was conducted through the HERB database, followed by molecular docking studies of these compounds with the LACTB2 protein. The integration and analysis of expression data obtained from 2294 CRC samples and 1286 noncancerous colorectal samples showed that LACTB2 was highly expressed in CRC. Immunohistochemistry performed on in-house tissue samples confirmed that LACTB2 protein expression was upregulated in CRC. CIBERSORT revealed lower B cell infiltration levels in the high LACTB2 expression group than in the low expression group. GO, KEGG, and GSEA analyses showed that LACTB2 expression and genes positively correlating with it were mainly related to DNA synthesis and repair, mitochondrial translational elongation and translational termination, phosphorylation, and mTORC1 signaling. Finally, molecular docking simulations confirmed the ability of quercitin to target and bind to LACTB2. This is the first study to demonstrate that LACTB2 is upregulated in CRC. LACTB2 promotes colorectal tumorigenesis and tumor progression.

SC-Unext: A Lightweight Image Segmentation Model with Cellular Mechanism for Breast Ultrasound Tumor Diagnosis.

Automatic breast ultrasound image segmentation plays an important role in medical image processing. However, current methods for breast ultrasound segmentation suffer from high computational complexity and large model parameters, particularly when dealing with complex images. In this paper, we take the Unext network as a basis and utilize its encoder-decoder features. And taking inspiration from the mechanisms of cellular apoptosis and division, we design apoptosis and division algorithms to improve model performance. We propose a novel segmentation model which integrates the division and apoptosis algorithms and introduces spatial and channel convolution blocks into the model. Our proposed model not only improves the segmentation performance of breast ultrasound tumors, but also reduces the model parameters and computational resource consumption time. The model was evaluated on the breast ultrasound image dataset and our collected dataset. The experiments show that the SC-Unext model achieved Dice scores of 75.29% and accuracy of 97.09% on the BUSI dataset, and on the collected dataset, it reached Dice scores of 90.62% and accuracy of 98.37%. Meanwhile, we conducted a comparison of the model's inference speed on CPUs to verify its efficiency in resource-constrained environments. The results indicated that the SC-Unext model achieved an inference speed of 92.72 ms per instance on devices equipped only with CPUs. The model's number of parameters and computational resource consumption are 1.46M and 2.13 GFlops, respectively, which are lower compared to other network models. Due to its lightweight nature, the model holds significant value for various practical applications in the medical field.

Genome-wide CRISPR off-target prediction and optimization using RNA-DNA interaction fingerprints.

The powerful CRISPR genome editing system is hindered by its off-target effects, and existing computational tools achieved limited performance in genome-wide off-target prediction due to the lack of deep understanding of the CRISPR molecular mechanism. In this study, we propose to incorporate molecular dynamics (MD) simulations in the computational analysis of CRISPR system, and present CRISOT, an integrated tool suite containing four related modules, i.e., CRISOT-FP, CRISOT-Score, CRISOT-Spec, CRISORT-Opti for RNA-DNA molecular interaction fingerprint generation, genome-wide CRISPR off-target prediction, sgRNA specificity evaluation and sgRNA optimization of Cas9 system respectively. Our comprehensive computational and experimental tests reveal that CRISOT outperforms existing tools with extensive in silico validations and proof-of-concept experimental validations. In addition, CRISOT shows potential in accurately predicting off-target effects of the base editors and prime editors, indicating that the derived RNA-DNA molecular interaction fingerprint captures the underlying mechanisms of RNA-DNA interaction among distinct CRISPR systems. Collectively, CRISOT provides an efficient and generalizable framework for genome-wide CRISPR off-target prediction, evaluation and sgRNA optimization for improved targeting specificity in CRISPR genome editing.

Chitosan-gentamicin conjugate attenuates heat stress-induced intestinal barrier injury via the TLR4/STAT6/MYLK signaling pathway: In vitro and in vivo studies.

Heat stress (HS) has a negative impact on animal health. A modified chitosan-gentamicin conjugate (CS-GT) was prepared to investigate its potential protective effects and mechanism of action on heat stress-induced intestinal mucosa injury in IPEC-J2 cells and mouse 3D intestinal organs in a mouse model. CS-GT significantly (P < 0.01) reversed the decline in transmembrane resistance and increased the FITC-dextran permeability of the IPEC-J2 monolayer fusion epithelium caused by heat stress. Heat stress decreased the expression of the tight binding proteins occludin, claudin1, and claudin2. However, pretreatment with CS-GT significantly increased (P < 0.01) the expression of these tight binding proteins. Mechanistically, CS-GT inhibited the activation of the TLR4/STAT6/MYLK signaling pathway induced by heat stress. Molecular docking showed that CS-GT can bind effectively with TLR4. In conclusion, CS-GT alleviates heat stress-induced intestinal mucosal damage both in vitro and in vivo. This effect is mediated, at least partly, by the inhibition of the TLR4/STAT6/MYLK signaling pathway and upregulation of tight junction proteins. These findings suggest that CS-GT may have therapeutic potential in the prevention and treatment of heat stress-related intestinal injury.

Slc9a1 plays a vital role in chitosan oligosaccharide transport across the intestinal mucosa of mice.

The mechanism underlying the intestinal transport of COS is not well understood. Here, transcriptome and proteome analyses were performed to identify potential critical molecules involved in COS transport. Enrichment analyses revealed that the differentially expressed genes in the duodenum of the COS-treated mice were mainly enriched in transmembrane and immune function. In particular, B2 m, Itgb2, and Slc9a1 were upregulated. The Slc9a1 inhibitor decreased the transport efficiency of COS both in MODE-K cells (in vitro) and in mice (in vivo). The transport of FITC-COS in Slc9a1-overexpressing MODE-K cells was significantly higher than that in empty vector-transfected cells (P < 0.01). Molecular docking analysis revealed the possibility of stable binding between COS and Slc9a1 through hydrogen bonding. This finding indicates that Slc9a1 plays a crucial role in COS transport in mice. This provides valuable insights for improving the absorption efficiency of COS as a drug adjuvant.

AZGP1 Up-Regulation is a Potential Target for Andrographolide Reversing Radioresistance of Colorectal Cancer.

Background: Radiation resistance is a challenge that limits the therapeutic benefit of colorectal cancer (CRC) treatment, but the mechanism underlying CRC radiation resistance remains unclear. Andrographolide shows a broad-spectrum anti-tumor effect in various malignancies, including CRC, its effect and how it functions in CRC initiation, and radiation have not been established. This study aimed to explore the mechanism of CRC radiation resistance and the potential mechanisms of andrographolide on CRC radiation. Methods: Two acquired radioresistant cell lines were established and high throughput sequencing was employed to screen out the differentially expressed genes. The expression of AZGP1, which was upregulated in the acquired radioresistant tissues, was verified by microarray data recomputing. The common targets of andrographolide, CRC initiation, and radiation resistance were obtained, and the corresponding functional enrichment and pathway analysis were performed. The interaction between AZGP1 and andrographolide was investigated using molecular docking. Results: AZGP1 was upregulated in both the radioresistant cell model and microarray data. Moreover, AZGP1 was upregulated in cancerous colorectal tissue and displayed a tendency toward elevated expression in patients with an unfavorable prognosis. AZGP1 was identified as the common target of andrographolide, colorectal cancer initiation, and radiotherapy resistance. Ultimately, the protein structure of AZGP1 proved to be closely intertwined with the crystal texture of andrographolide. Conclusion: AZGP1 is recognized as a crucial factor for both CRC initiation and radioresistance. Andrographolide may affect the radioresistance of CRC via the targeting of AZGP1. Thus, the combination of andrographolide and AZGP1 intervention might be a promising strategy for improving the treatment benefit of CRC radiotherapy.

Downregulated miR-150-5p in the Tissue of Nasopharyngeal Carcinoma.

The clinical significance and potential targets of miR-150-5p have not been elucidated in nasopharyngeal carcinoma (NPC). The pooled analysis based on 539 NPC samples and 75 non-NPC nasopharyngeal samples demonstrated that the expression of miR-150-5p was down-regulated in NPC, with the area under the curve being 0.89 and the standardized mean difference being -0.66. Subsequently, we further screened the differentially expressed genes (DEGs) of 14 datasets, including 312 NPC samples and 70 non-NPC nasopharyngeal samples. After the DEGs were narrowed down with the predicted targets from the miRWalk database, 1316 prospective target genes of miR-150-5p were identified. The enrichment analysis suggested that "pathways in cancer" was the most significant pathway. Finally, six hub genes of "pathways in cancer", including EGFR, TP53, HRAS, CCND1, CDH1, and FGF2, were screened out through the STRING database. In conclusion, the down-regulation of miR-150-5p modulates the tumorigenesis and progression of NPC.

Characterization of the mechanism of Scutellaria baicalensis on reversing radio-resistance in colorectal cancer.

Scutellaria baicalensis (SB) has been shown to improve the therapeutic effects of colorectal cancer (CRC) and perform well for reversing radio-resistance in different cancers. However, its potential function and mechanism related to radio-resistance in CRC has not been explored. A radio-resistant human CRC cell line (HCT116R) was applied. A network pharmacological analysis was performed to reveal the potential mechanism of SB for reversing radio-resistance in CRC, and computational pathological analysis was applied to indicate the clinicopathological significance of the key targets. Then, our hypothesis was further verified by molecular docking. The network pharmacology analysis showed that wogonin is the key compound of SB for reversing the radio-resistance of CRC. A Kyoto Encyclopedia of Genes and Genomes analysis showed that the genes for SB that reverse radio-resistance in CRC are mainly involved in steroid hormone biosynthesis. An enrichment analysis pointed out that Sulfotransferase family 2B member 1 (SULT2B1) is a potentially vital gene. SULT2B1 was demonstrated as being highly expressed in CRC and upregulated in radio-resistant rectal tissues or cell lines. A CCK-8 and clone formation test showed that the viability and clone formation ability of HCT116R were significantly decreased by wogonin combined with radiotherapy, compared to radiotherapy alone. By contrast, flow cytometry revealed that the apoptosis of HCT116R was significantly increased when wogonin treatment combined with radiotherapy, compared with radiotherapy alone. Molecular docking verification indicated that SULT2B1 and wogonin have a good binding ability. Taken together, SULT2B1 may be the potential drug target in treating radio-resistant CRC. Wogonin may be the core compound of SB for reversing radio-resistance in CRC by targeting SULT2B1.

Chitosan oligosaccharide improves the mucosal immunity of small intestine through activating SIgA production in mice: Proteomic analysis.

Chitosan oligosaccharide (COS) plays a vital role in improving the host system and mucosal immune function. So far, the impact of COS on mucosal immune response in the early stage of oral administration is not well understood. Herein, the distribution of COS after oral gavage and the protein expression changes related to innate immune by tandem mass tag (TMT)-based proteomic analysis were investigated. The results revealed that COS was mainly distributed in the stomach, duodenum, and kidney and increased the number of monocytes and lymphocytes in peripheral blood. A total of 21,677 proteins and 7,483 protein groups were identified. Among them, 338 significant differentially expressed proteins were screened, including 205 upregulated and 133 downregulated. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that the intestinal immune network for the IgA production pathway was activated, pIgR, MHCI, MHCII, Itgb2, Itgb7, and B2m were significantly increased (P < 0.05). Furthermore, the expression of the above molecular genes was detected by enzyme-linked immunosorbent assay (ELISA), western blotting, and quantitative real-time PCR. We found that the expressions of IgA, MHCII, TGF-ß1, IL-6, and pIgR were significantly increased (P < 0.05) 1 h after exposure to COS. The protein and mRNA expression of pIgR and MHCI were significantly increased (P < 0.05) at 0.5 h, while the AID protein level was significantly increased (P < 0.05) 1.5 h after COS exposure. The expression of MHCII and H2-Q10 was significantly increased (P < 0.05) by 1 h and 2 h post-exposure to COS. In conclusion, oral administration of COS can significantly enhance intestinal mucosal immunity in mice by activating the SIgA secretion pathway. These results suggest that COS can be used as an oral vaccine or drug adjuvant for small intestinal mucosa.

Upregulation of the transmembrane protease serine 3 mRNA level in radioresistant colorectal cancer tissues.

Aim: To investigate the clinical role of transmembrane protease serine 3 (TMPRSS3) in radioresistance and prognosis of colorectal cancer (CRC). Methods: Standardized mean difference (SMD) and summary area under the curve (AUC) of TMPRSS3 were calculated by combining all available high-throughput data globally. The prognostic significance of TMPRSS3 was determined by Kaplan-Meier and Cox regression analyses. Results:TMPRSS3 was remarkably upregulated in 198 CRC radioresistant cases compared with nonradioresistance (SMD = 0.38, AUC = 0.71). Overexpression of TMPRSS3 was observed in 1601 CRC patients compared with control subjects without CRC. TMPRSS3 was a risk factor for disease-free survival of CRC with the summarized hazard ratio 1.28. Conclusion: TMPRSS3 contributes to the radioresistance and unfavorable prognosis of CRC.

Downregulation of MicroRNA-1 and Its Potential Molecular Mechanism in Nasopharyngeal Cancer: An Investigation Combined with In Silico and In-House Immunohistochemistry Validation.

BACKGROUND: This study was aimed at elucidating the molecular biological mechanisms of microRNA-1 (miR-1) in nasopharyngeal carcinoma (NPC). METHOD: In this study, we performed a pooled analysis of miR-1 expression data derived from public databases, such as GEO, ArrayExpress, TCGA, and GTEx. The miRWalk 2.0 database, combined with the mRNA microarray datasets, was used to screen the target genes, and the genes were then subjected to Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analysis using the DAVID 6.8 database. We then used the STRING 11.0 database and Cytoscape 3.80 software to construct a protein-protein interaction (PPI) network for screening hub genes. Immunohistochemistry (IHC) was further used to validate the expression of hub genes. Finally, potential therapeutic agents for NPC were screened by the Connectivity Map (cMap) database. RESULTS: Pooled analysis showed that miR-1 expression was significantly decreased in NPC (SMD = -0.57; P < 0.05). The summary receiver operating characteristic curve suggested that miR-1 had a good ability to distinguish cancerous tissues from noncancerous tissues (AUC = 0.78). The results of GO analysis focused on mitotic nuclear division, DNA replication, cell division, cell adhesion, extracellular space, kinesin complex, and extracellular matrix (ECM) structural constituent. The KEGG analysis suggested that the target genes played a role in key signaling pathways, such as cell cycle, focal adhesion, cytokine-cytokine receptor interaction, ECM-receptor interaction, and PI3K/Akt signaling pathway. The PPI network suggested that cyclin-dependent kinase 1 (CDK1) was the hub gene, and the CDK1 protein was subsequently confirmed to be significantly upregulated in NPC tissues by IHC. Finally, potential therapeutic drugs, such as masitinib, were obtained by the cMap database. CONCLUSION: miR-1 may play a vital part in NPC tumorigenesis and progression by regulating focal adhesion kinase to participate in cell mitosis, regulating ECM degradation, and affecting the PI3K/Akt signaling pathway. miR-1 has the potential to be a therapeutic target for NPC.

A Comprehensive Analysis of the Colonic Flora Diversity, Short Chain Fatty Acid Metabolism, Transcripts, and Biochemical Indexes in Heat-Stressed Pigs.

Heat stressed pigs show typical characteristics of inflammatory bowel disease (IBD). However, little is known about the pathogenesis of heat stress (HS)-induced IBD in pigs. In this study, we determined the effects of HS on colon morphology, intestinal microbiota diversity, transcriptome genes (transcripts), and short chain fatty acids (SCFAs) metabolism in pigs. In addition, the correlation among these parameters was analyzed by weighted gene co-expression network analysis. Results showed that the liver and kidney functions related to blood biochemical indexes were partially changed in pigs under HS. Furthermore, the levels of diamine oxidase and D-lactic acid were significantly increased, whereas the levels of secretory immunoglobulin A were decreased. The integrity of colonic tissue was damaged under HS, as bleeding, lymphatic infiltration, and villi injury were observed. The concentrations of SCFAs in the colon, such as acetic acid and butyric acid, were decreased significantly. In addition, the composition of colon microbiota, such as decrease in Lactobacillus johnsonii, Lactobacillus reuteri and increase in Clostridium sensu stricto 1 of day 7 and 14 while under HS. These changes were associated with changes in the concentration of SCFAs and biochemical indexes above mentioned. Differentially expressed genes were enriched in the nucleotide-binding oligomerization domain-like receptor signaling pathway, Th17 cell differentiation, and IBD pathway, which were also associated with the changes in SCFAs. Thus, the structure, diversity of intestinal microorganisms, and changes in the levels of SCFAs in colon of heat stressed pigs changed significantly, contributing to the activation of immune response and inflammatory signal pathways and causing abnormal physiological and biochemical indexes and intestinal mucosal damage. These results highlight the interconnections between intestinal microbiota, SCFAs, and immune response and their role in the pathogenesis of stress induced IBD therapy.

Effect of chitosan on blood profile, inflammatory cytokines by activating TLR4/NF-κB signaling pathway in intestine of heat stressed mice.

Heat stress can significantly affect the immune function of the animal body. Heat stress stimulates oxidative stress in intestinal tissue and suppresses the immune responses of mice. The protecting effects of chitosan on heat stress induced colitis have not been reported. Therefore, the aim of this study was to investigate the protective effects of chitosan on immune function in heat stressed mice. Mice were exposed to heat stress (40 °C per day for 4 h) for 14 consecutive days. The mice (C57BL/6J), were randomly divided into three groups including: control group, heat stress, Chitosan group (LD: group 300 mg/kg/day, MD: 600 mg/kg/day, HD: 1000 mg/kg/day). The results showed that tissue histology was improved in chitosan groups than heat stress group. The current study showed that the mice with oral administration of chitosan groups had improved body performance as compared with the heat stress group. The results also showed that in chitosan treated groups the production of HSP70, TLR4, p65, TNF-α, and IL-10 was suppressed on day 1, 7, and 14 as compared to the heat stress group. In addition Claudin-2, and Occludin mRNA levels were upregulated in mice receiving chitosan on day 1, 7, and 14 of heat stress. Furthermore, the IL-6, IL-10, and TNF-α plasma levels were down-regulated on day 1, 7, and 14 of heat stress in mice receiving the oral administration of chitosan. In conclusion, the results showed that chitosan has an anti-inflammatory ability to tolerate hot environmental conditions.

Terpinen4-ol inhibits heat stress induced inflammation in colonic tissue by Activating Occludin, Claudin-2 and TLR4/NF-κB signaling pathway.

Heat stress has severe implications on the health of mice involving intestinal mucosal barrier damage and dysregulated mucosal immune response. This study was designed with long-term heat stress to detect the protective effect of terpinen4-ol on body weight, colon length, organ index, morphological structure, inflammatory cytokines expression, Claudin-2, Occludin, and TLR4 signaling pathway of colonic tissue in mice under heat stress. A study found that oral administration of terpinen4-ol helped against mortality and intestinal inflammation in a mouse model of acute colitis induced by heat stress (40 °C per day for 4 h) exposed for 14 consecutive days. The mice were divided into five groups including control, heat stress, terpinen4-ol low dose (TER LD: 5 mg/kg), medium dose (TER MD: 10 mg/kg), and high dose (TER HD: 20 mg/kg) group. Our study showed that the heat-stress terpinen4-ol group had improved body weight, colon length, and organ index, the number of white blood cells, lymphocytes, and neutrophils in the blood as compared to the heat stress group. In addition, results showed that heat stress upregulated the expression of TLR4, p65, TNF-α, and IL-10. While, in mice receiving the oral administration of terpinen4-ol, the production of TNF-α, IL-10, TLR4, and p65 was suppressed on day 1, 7, and 14 of heat stress. In addition Claudin-2, Occludin mRNA levels were upregulated in mice receiving terpinen4-ol on day 1, 7, and 14 of heat stress. Furthermore, the IL-6, IL-10, TNF-α serum levels were also upregulated in mice under heat stress, but in mice receiving the oral administration of terpinen4-ol, the IL-6, IL-10, TNF-α level was down-regulated on day 1, 7, and 14 of heat stress. Histomorphological examination found that as compared to the control group, the muscle layer thickness and villi height of mice in the heat stress group were significantly reduced, while the changes of the above indicators in the terpinene4-ol groups were improved than those in the heat stress group. In conclusion, the terpinen4-ol has a protective effect on colonic tissue damage induced by heat stress.

Active Enhancer Assessment by H3K27ac ChIP-seq Reveals Claudin-1 as a Biomarker for Radiation Resistance in Colorectal Cancer.

BACKGROUND: Colorectal cancer (CRC) represents the third most common malignant tumor in the worldwide. Radiotherapy is the common therapeutic treatment for CRC, but radiation resistance is often encountered. ChIP-seq of Histone H3K27 acetylation (H3K27ac) has revealed enhancers that play an important role in CRC. This study examined the relationship between an active CRC enhancer and claudin-1 (CLDN1), and its effect on CRC radiation resistance. METHODS: The target CRC genes of active enhancers were obtained from public H3K27ac ChIP-seq, and the genes highly expressed in radio-resistant CRC were screened and intersected with enhancer-driven genes. The clinical roles of CLDN1 in radiation resistance were examined using the t-test, standard mean deviation (SMD), summary receiver operating characteristic curve and Kaplan-Meier curves. The co-expressed genes of CLDN1 were calculated using Pearson Correlation analysis, and Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes and Gene Set Variation Analysis (GSVA) analyses were used to examine the molecular mechanisms of CLDN1. RESULTS: Total 13 703 CRC genes were regulated by enhancers using 58 H3K27ac ChIP-seq. Claudin-1 (CLDN1) was enhancer-driven and notably up-regulated in CRC tissues compared to non-CRC controls, with a SMD of 3.45 (95 CI % = .56-4.35). CLDN1 expression was increased in radiation-resistant CRC with a SMD of .42 (95% CI = .16-.68) and an area under the curve of .74 (95% CI = .70-.77). The cell cycle and immune macrophage levels were the most significant pathways associated with CLDN1. CONCLUSION: CLDN1 as an enhancer-regulated gene that can boost radiation resistance in patients with CRC.

Baicalin Alleviates LPS-Induced Oxidative Stress via NF-κB and Nrf2-HO1 Signaling Pathways in IPEC-J2 Cells.

Baicalin is a natural plant extract with anti-inflammatory and anti-oxidant activities. However, the molecular mechanism of baicalin on oxidative stress in IPEC-J2 cells exposed to LPS remains to be unclear. In this study, LPS stimulation significantly increased Toll-like receptor 4, tumor necrosis factor-α, and interleukins (IL-6 and IL-1ß) expression in IPEC-J2 cells, and it activated the nuclear factor (NF-κB) expression. While, baicalin exerted anti-inflammatory effects by inhibiting NF-κB signaling pathway. LPS stimulation significantly increased the levels of the oxidative stress marker MDA, inhibited the anti-oxidant enzymes catalase and superoxide dismutase, which were all reversed by baicalin pre-treatment. It was found that baicalin treatment activated the nuclear import of nuclear factor-erythroid 2 related factor 2 (Nrf2) protein, and significantly increased the mRNA and protein expression of its downstream anti-oxidant factors such as heme oxygenase-1 and quinone oxidoreductase-1, which suggested that baicalin exerted anti-oxidant effects by activating the Nrf2-HO1 signaling pathway. Thus, pretreatment with baicalin inhibited LPS - induced oxidative stress and protected the normal physiological function of IPEC-J2 cells via NF-κB and Nrf2-HO1 signaling pathways.

Prevalence of abnormal uterine bleeding according to new International Federation of Gynecology and Obstetrics classification in Chinese women of reproductive age: A cross-sectional study.

The PALM-COEIN classification for causes of abnormal uterine bleeding (AUB) was proposed by the International Federation of Gynecology and Obstetrics (FIGO) in 2011, which has been gradually applied in the diagnosis of AUB in the past 2 years in China. However, there are no reports yet on the causes of chronic AUB among Chinese women with this new classification system.The purpose of this study was to describe the prevalence of the causes of chronic AUB among Chinese women of reproductive age using the PALM-COIEN classification system.This is a cross-sectional study. Beijing Shijitan Hospital, Capital Medical University.A total of 1053 women aged 15 to 55 years with chronic AUB were evaluated between November 2016 and May 2017.Prevalence of the causes of chronic AUB using the PALM-COEIN classification. AUB-O was the most frequent finding in women with chronic AUB, accounting for 608 (57.7%) cases. AUB-P was found in 171 (16.2%) women, AUB-L in 130 (12%) women, AUB-A in 52 (4.94%) women, AUB-E in 28 (2%) women, AUB-I in 23 (2%) women, AUB-M in 20 (1.9%) women, AUB-C in 10 (1%) women, and AUB-N in 10 (0.9%) women.Ovulatory dysfunction (AUB-O) is the most common cause of AUB among the nonstructural causes. Endometrial polyps (AUB-P) are the most common among the structural causes, followed by uterine fibroids (AUB-L) and uterine adenomyosis (AUB-A).