Background and Aims:Pancreatic ductal adenocarcinoma(PDAC)is a highly malignant digestive system tumor with an inferior prognosis,and its early diagnosis and treatment remain significant challenges.In recent years,RNA methylation modifications(such as m6A and m5C)have attracted considerable attention for their roles in tumor development;however,their regulatory mechanisms and clinical significance in PDAC remain unclear.This study was conducted to identify prognosis-related long noncoding RNAs(lncRNAs)associated with m6A and m5C in PDAC,construct a reliable prognostic prediction model,and explore their relationship with the tumor immune microenvironment.Methods:Based on RNA-seq data from the TCGA-PDAC cohort,differentially expressed lncRNAs(DElncRNAs)related to m6A and m5C were identified through differential expression analysis and Pearson correlation analysis.The samples were randomly divided into a training set(n=89)and a validation set(n=89).Key DElncRNAs were selected using LASSO-Cox regression to construct a prognostic model,and patients were categorized into high-and low-risk groups based on risk scores.Kaplan-Meier survival analysis,ROC curves,and multivariate Cox regression were used to evaluate the model's predictive performance.Furthermore,CIBERSORT and ESTIMATE scores were used to analyze immune cell infiltration characteristics and tumor microenvironment(TME)differences between the high-and low-risk groups.Results:To construct the prognostic model,four m6A-and m5C-related DElncRNAs(LINC00857,LINC02038,TSPOAP1-AS1,and TRPC7-AS1)were identified.Patients in the high-risk group had significantly lower overall survival than those in the low-risk group(P<0.05),and the risk score was an independent prognostic factor for PDAC(HR=1.551,95%CI=1.297-1.854,P<0.001).ROC curve analysis showed that the risk score model exhibited high predictive efficiency in both the training and validation sets(AUC values for 1,3,and 5 years:0.766,0.875,0.879;0.685,0.711,0.792,respectively).Immune analysis revealed increased infiltration of M0 macrophages with lower TME scores in the high-risk group(all P<0.05),suggesting an immunosuppressive microenvironment.Conclusion:This study successfully established a PDAC prognostic model based on m6A-and m5C-related DElncRNAs and confirmed its independent predictive value.High-risk patients exhibited M0 macrophage enrichment and immunosuppressive microenvironment characteristics,possibly contributing to poor prognosis.

Background and Aims:Pancreatic ductal adenocarcinoma(PDAC)is a highly malignant digestive system tumor with an inferior prognosis,and its early diagnosis and treatment remain significant challenges.In recent years,RNA methylation modifications(such as m6A and m5C)have attracted considerable attention for their roles in tumor development;however,their regulatory mechanisms and clinical significance in PDAC remain unclear.This study was conducted to identify prognosis-related long noncoding RNAs(lncRNAs)associated with m6A and m5C in PDAC,construct a reliable prognostic prediction model,and explore their relationship with the tumor immune microenvironment.Methods:Based on RNA-seq data from the TCGA-PDAC cohort,differentially expressed lncRNAs(DElncRNAs)related to m6A and m5C were identified through differential expression analysis and Pearson correlation analysis.The samples were randomly divided into a training set(n=89)and a validation set(n=89).Key DElncRNAs were selected using LASSO-Cox regression to construct a prognostic model,and patients were categorized into high-and low-risk groups based on risk scores.Kaplan-Meier survival analysis,ROC curves,and multivariate Cox regression were used to evaluate the model's predictive performance.Furthermore,CIBERSORT and ESTIMATE scores were used to analyze immune cell infiltration characteristics and tumor microenvironment(TME)differences between the high-and low-risk groups.Results:To construct the prognostic model,four m6A-and m5C-related DElncRNAs(LINC00857,LINC02038,TSPOAP1-AS1,and TRPC7-AS1)were identified.Patients in the high-risk group had significantly lower overall survival than those in the low-risk group(P<0.05),and the risk score was an independent prognostic factor for PDAC(HR=1.551,95%CI=1.297-1.854,P<0.001).ROC curve analysis showed that the risk score model exhibited high predictive efficiency in both the training and validation sets(AUC values for 1,3,and 5 years:0.766,0.875,0.879;0.685,0.711,0.792,respectively).Immune analysis revealed increased infiltration of M0 macrophages with lower TME scores in the high-risk group(all P<0.05),suggesting an immunosuppressive microenvironment.Conclusion:This study successfully established a PDAC prognostic model based on m6A-and m5C-related DElncRNAs and confirmed its independent predictive value.High-risk patients exhibited M0 macrophage enrichment and immunosuppressive microenvironment characteristics,possibly contributing to poor prognosis.

Objective: To analyze the situation of AIDS knowledge and discrimination among freshmen in Chengdu city, and to explore possible effects of AIDS knowledge on discrimination. Methods: A cluster random sampling was employed to investigate 1 053 college students from 11 universities in Chengdu about their HIV/AIDS knowledge and discrimination. The scores of AIDS knowledge and discrimination of students with different characteristics were analyzed, and the influence path of AIDS knowledge on AIDS discrimination were further analyzed based on different peer relationships. Results: The total scores of AIDS knowledge was negatively correlated to AIDS discrimination( r s =-0.13, P <0.01). After adjusting for confounding factors, the total score of AIDS knowledge was associated with the total score of AIDS discrimination( β =-0.12, P <0.01). AIDS knowledge played a role in AIDS discrimination in intimate, general and unfamiliar peer relationships, with standardized path coefficients of -0.20, -0.24 and -0.18 respectively( P <0.01). Conclusion AIDS knowledge are correlated with discrimination among freshmen under different peer relationships. More anti-AIDS discrimination courses should be added to AIDS education to reduce the students’ fear and stigma of HIV/AIDS patients and related risk groups.