Breast cancer is one of the primary threats towomen's health worldwide. However, the molecular mecha-nisms underlying the development of breast cancer remain to befully elucidated. The present study aimed to investigate specifictarget gene expression profiles in breast cancer tissues in generaland in different breast cancer stages, as well as to explore theirfunctions in tumor development. For integrated analysis, a totalof 5 gene expression profiling datasets for 3 different stages ofbreast cancer (stages I-III) were downloaded from the GeneExpression Omnibus of the National Center for BiotechnologyInformation. Pre-processing of these datasets was performedusing the Robust Multi-array Average algorithm and globalrenormalization was performed for all studies. Differentiallyexpressed genes between breast cancer patients and controlswere estimated using the empirical Bayes algorithm. TheDatabase for Annotation, Visualization and IntegratedDiscovery web server was used for analyzing the enrichmentof the differentially expressed genes in Gene Ontology termsof the category biological process and in Kyoto Encyclopediaof Genes and Genomes pathways. Furthermore, breast cancertarget genes were downloaded from the Thomson ReutersIntegrity Database. We merged these target genes with the genesin breast cancer datasets. Analysis of anti-breast cancer genenetworks was performed using the Genome-scale IntegratedAnalysis of Gene Networks in Tissues web server. The resultsdemonstrated that the normal functions of the cell cycle, cellmigration and cell adhesion were altered in all stages of breastcancer. Furthermore, 12 anti‑breast cancer genes were identifiedto be dysregulated in at least one of the three stages. Among allof these genes, ribonucleotide reductase regulatory subunit M2(RRM2) exhibited the highest degree of interaction with otherinteracting genes. Analysis of the network interactions revealedthat the transcription factor of RRM2 is crucial for cancer devel-opment. Other genes, including mucin 1, progesterone receptorand cyclin-dependent kinase 5 regulatory subunit associatedprotein 3, also exhibited a high degree of interaction with theassociated genes. In conclusion, several key anti-breast cancergenes identified in the present study are mainly associated withthe regulation of the cell cycle, cell migration, cell adhesion andother cancer-associated cell functions, particularly RRM2.