Prognostic Analysis And Clinical Significance Of Related Genes In Pancreatic Cancer

Objective: The aim of this study was to investigate the differential expression and survival analysis of PAAD-related genes in tumor tissues and healthy human pancreatic tissues at the bioinformatics level using transcriptomic data from patients with advanced pancreatic adenocarcinoma(PAAD)and PAAD samples from the TCGA database with high-throughput sequencing,and to further analyze the above genes in relation to tumor immune infiltration,treatment resistance,tumor heterogeneity,etc,to explore the potential clinical value of mutated genes in this study in terms of prognosis and treatment.Methods:(1)The clinicopathological data of nine patients with advanced PAAD who were admitted to our hospital from January 2019 to December 2022 and tested for circulating tumor DNA(ctDNA)genes in peripheral blood were collected.Patients were numbered 1-9in order of inclusion,and their clinicopathological characteristics and the status of 19 mutated genes in peripheral blood before treatment were analyzed.The Mutation Taster database was used to analyze the pathogenicity of KRAS mutation sites in patients with PAAD.The R language(version 4.1.2)and the matching version of the R Bioconductor software package were used to map the distribution of 19 mutated genes in 9 patients with advanced PAAD.The data processing was processed using SPSS26.0 software and the Kaplan-Meier method to draw the survival curve.(2)The survival data of 149 PAAD samples and their transcriptome data related to 19 mutated genes that appeared in late PAAD patients in this study were downloaded from the CBio Portal database.Based on the GEPIA2 database,the expression differences of the above 19 mutated genes in pancreatic tumor tissues and normal pancreatic tissues were analyzed,and according to the optimal cut-off value of gene expression,they were divided into high-value group and low-value group for survival analysis.Based on the GO database and the KEGG database,the biological processes,molecular functions,and signaling pathways of PAAD-related genes that were significantly enriched in this study were revealed.The tumor-promoting gene CDK6 was selected for further single-cell sequencing analysis and immune infiltration analysis.Data were analyzed using the R language(version 4.1.2)and a matching version of the R Bioconductor package.Survival curves were drawn by the Kaplan-Meier method,and the Log-Rank test was used to compare whether there was a statistically significant difference in survival time between the two groups with high or low expression of each gene.Spearman correlation analysis was used to evaluate the correlation between CDK6 gene expression and infiltrating immune cells.P<0.05 is statistically significant.Results:(1)A total of 9 patients with advanced PAAD were included,and all cases showed disease progression or death with a median PFS of 4.50 months(95% CI: 3.331～5.669).Six patients presenting KRAS point mutations were patients #1 to #4,#8,and #9,with specific mutation sites: G12 V and G12 D,with mutation abundance of 1.5%,1.87%,12.73%,8.9%,0.4%,and 5.64%,in that order.There were three patients with TP53 point mutations,patients#4,#6,and #7,respectively,with specific mutation sites: R273 C,G266V,G154 S,and R379 H,in which patients #6 were sent peripheral blood specimens for genetic testing before and after treatment,respectively,and all showed TP53 mutations with MAF values of 2.67%and 0.6%,and patients #4 and #7 had TP53 MAF values of 3.51% and 1.49%,respectively.The pathogenicity analysis of KRAS mutation sites showed that both G12 V and G12 D mutation sites were missense mutations with highly conserved sequences and 99.9%pathogenicity probability.(2)The expression levels of FGFR1 and FGFR3 were lower in pancreatic tumor tissues than in normal tissues,and the expression levels of the remaining 17 mutated genes were higher in pancreatic tumor tissues than in normal tissues.increased expression levels of ABL1,FGFR2,FGFR4,FLT3,IGF1 R,JAK3,and genes improved patient prognosis(P <0.05),KRAS,BRCA1,CDK6,EGFR,ERBB2,and MET gene expression levels were poor prognostic factors in PAAD patients(P < 0.05),while ALK,BRCA2,FGFR1,FGFR3,KIT,TP53,and JAK1 gene expression levels were not significantly correlated with patient OS(P > 0.05).GO and KEGG enrichment analysis showed that the above CDK6 gene expression was associated with infiltrating immune cells within the tumor microenvironment.Conclusions:(1)Elevated expression levels of ABL1,FGFR2,FGFR4,FLT3,IGF1R,and JAK3 genes improve patient prognosis;elevated expression levels of KRAS,BRCA1,CDK6,EGFR,ERBB2,and MET genes are poor prognostic factors in PAAD patients.(2)CDK6 gene is involved in tumor microenvironment remodeling.(3)CDK6 gene expression level can regulate the proportion of immune cell infiltration within the tumor microenvironment.