Analysis Of Differentially Expressed Genes Associated With Breast Cancer Development Based On Ductal Carcinoma In Situ And Invasive Ductal Carcinoma Of The Breast

Objective: Breast cancer is the most common cancer in the world and the fifth leading cause of cancer death.The most common non-invasive breast cancer is ductal carcinoma in situ(DCIS),while the most common pathology is invasive ductal carcinoma.In this study,DCIS and IDC differentially expressed genes were investigated by bioinformatics and clinical pattern recognition to examine important tumour cell genes that breach the basement membrane during breast cancer development and provide a potential theoretical basis for breast cancer initiation and progression and clinical research.Methods: Samples of DCIS and IDC patients were taken from the GEO database and DEGs were validated by performing GO and KEGG feature enthalpy coding of DEGs using R software.Protein interactions were analyzed using the STRING online database,and a PPI protein interaction network was created;Cytoscape software was used to visualize PPIs,and the Cyto Hubba plugin was used to calculate hub genes.To analyze the correlation between the expression level of hub gene and clinicopathologic stage of breast cancer and clinical prognosis of patients.The GEPIA database was used to test whether the selected hub genes were associated with breast cancer development and progression.Finally,clinical samples were collected and immunohistochemical detection of hub gene protein expression in normal breast tissue,ductal carcinoma in situ and invasive ductal carcinoma in situ in breast tissue was performed to further elucidate the association between the hub gene and breast cancer development and progression.Results: Through the collation and analysis of GSE3893 and GSE21422 chip data,a total of 653 DEGs(including 169 up-regulated and 484 down-regulated differentially expressed genes)were obtained,and the target genes with the highest number of clinical traits were screened out: baculoviral IAP repeat containing 5(BIRC5),prolyl 4-hydroxylase beta polypeptide(P4HB),peroxiredoxin 1(PRDX1)and fibronectin1(FNl).The high expression of BIRC5 was correlated with the T staging of breast cancer(P<0.05),while P4 HB,PRDX1 and FN1 were not correlated with the staging of breast cancer.The higher the expression of the four nodal genes,the lower the overall survival of patients.Immunohistochemistry showed that the expression of BIRC5,P4 HB,and PRDX1 was higher in invasive breast cancer than in adjacent tissues;the expression of BIRC5,P4 HB,and PRDX1 was higher in the IDC group than in the DCIS group;FN1 expression did not differ between invasive and paracrine breast cancer,but was higher in the DCIS group than in the IDC group.Conclusions: BIRC5,P4 HB and PRDX1 are key genes that promote the occurrence and development of breast cancer.BIRC5 is significantly correlated with T staging,and the high expression of the four genes reduces the overall survival of patients.The expression level of FN1 in DCIS is higher than that in IDC,which may be related to breast cancer invasion.