Identification of key genes involved in HER2-positive breast cancer.

As an invasive cancer, breast cancer is the most common tumour in women and is with high mortality. To study the mechanisms of HER2-positive breast cancer, we analyzed microarray of GSE52194. GSE52194 was downloaded from Gene Expression Omnibus including 5 HER2-positive breast cancer samples and 3 normal breast samples. Using cuffdiff software, differentially expressed genes (DEGs) and differentially expressed long non-coding RNAs (DE-lncRNAs) were screened. Functions of the DEGs were analyzed by Gene Ontology (GO) and pathway enrichment analyses. Then, protein-protein interaction (PPI) network of the DEGs was constructed using Cytoscape and modules of the PPI network were screened by CFinder. Moreover, lncRNA-DEG pairs were screened. Total 209 lncRNA transcriptions were predicted, and 996 differentially expressed transcriptions were screened. Besides, FOS had interaction relationships with EGR1 and SOD2 separately in module E and F of the PPI network for the DEGs. Moreover, there were many lncRNA-DEG pairs (e.g. TCONS_00003876-EGR1, TCONS_00003876-FOS, lnc-HOXC4-3:1-FOS, lnc-HOXC4-3:1-BCL6B, lnc-TEAD4-1:1-FOS and lnc-TEAD4-1:1-BCL6B), meanwhile, co-expressed DEGs of TCONS_00003876, lnc-HOXC4-3:1 and lnc-TEAD4-1:1 were enriched in p53 signaling pathway, MAPK signaling pathway and cancer-related pathways, respectively. ANXA1, EGR1, BCL6, SOD2, FOS, TCONS_00003876, lnc-HOXC4-3:1 and lnc-TEAD4-1:1 might play a role in HER2-positive breast cancer.