Relationship Between ASF1B Expression And ATGs And Prognosis In Gastric Cancer

Objective:The key genes of gastric cancer were obtained from biological information database,and verified by real-time quantitative RT-PCR and immunohistochemistry.The relationship between them and autophagy-related proteins and their influence on disease-free survival time of patients were analyzed,which provided theoretical basis for targeted diagnosis and treatment and basic research in the future.Materials and methods:1)Download GSE118916,GSE33651 and GSE26899 data sets from GEO database,and use online tools to screen out coexpression difference genes;2)Download the clinical and sequencing data of gastric adenocarcinoma from TCGA database,analyze the differences by using Limma package in R language,and identify the original data by classical Bayesian method to obtain Differentially Expressed Genes(DEGs);3)Sum up that differential genes,construct a protein interaction network(PPI)diagram of the differential genes by using an online database STRING,and perform modular analysis by using MCODE software under Cytoscape software to screen pivotal genes;4)DAVID online tool and UCSC were used to analyze the functional enrichment of key genes and construct the hierarchical cluster diagram of core genes.Finally,Kaplan-Meier model was used to analyze the prognosis;5)Collecting 32 cases of gastric cancer patients with complete clinicopathological data from January 2017 to June 2019.Gastric cancer tissues and adjacent tissues were taken as experimental groups,and normal tissues were taken as control groups.Immunohistochemistry and Q-PCR were used to verify the expression of ASF1B and autophagy-related proteins(LC3 and Beclin1)in different tissues,to further explore the correlation between ASF1B and autophagy,and to analyze the effect of its expression level on patients.Results:1)A total of 43 pivotal genes were screened from bioinformatics database,among which the high expression of ASF1B,AURKB,BIRC5,MKi67,MYBL2,P100,PKMYT1,PLK1 and UBE2C was related to the poor overall survival rate(OS)of gastric cancer patients.further analysis showed that ASF1B was highly correlated with the death risk of gastric cancer patients(HR=1.79 p<0.001);2)The results of Q-PCR showed that the expression levels of ASF1B,LC3 and Beclin1 m RNA in gastric cancer tissues were significantly different from those in adjacent tissues and normal tissues(p<0.05),but there was no significant difference between adjacent tissues and normal tissues(p>0.05).The expression of ASF1B was positively correlated with LC3 and Beclin1 in cancer tissues(rs=0.445 rs=0.451 p<0.05);3)Immunohistochemistry(IHC)showed that the expression levels of ASF1B,LC3 and Beclin1 in gastric cancer tissues were significantly different from those in adjacent and normal tissues(P<0.05),but there was no significant difference between adjacent and normal tissues(P>0.05).The expression of ASF1B was positively correlated with LC3 and Beclin1 in cancer tissues(rs=0.790 rs=0.564 p<0.05);4)The results of analyzing the influence of ASF1B expression level on PFS of gastric cancer patients showed that the median disease-free progression time of positive expression group was 16 months and the 2-year PFS was 11.7%,while the negative expression group did not reach the median disease-free progression period,and its 2-year PFS was 58.3%.There is a significant difference between the two groups(?~22=5.394,P=0.02).Conclusions:1)based on bioinformatics analysis,the results show that the overexpression of ASF1B is significantly related to the death risk of gastric cancer patients;2)The expression trend of ASF1B in cancer tissues of gastric cancer patients is increasing,while the expression trend of ASF1B in adjacent tissues and normal tissues is not obvious;3)The expression levels of ASF1B and autophagy-related proteins(LC3,Beclin1)were positively correlated in gastric cancer tissues;4)Overexpression of ASF1B is a risk factor for poor long-term prognosis(PFS)of gastric cancer patients.