Gene regulatory networks (GRNs) affect numerous cellular processes and every process of life, and abnormalities of GRN lead to breast cancer. Transcription factors (TFs) and microRNAs (miRNAs) are two of the best-studied gene regulatory mechanisms. However, the architecture and feature of GRNs by TFs and miRNAs in breast cancer and its subtypes were unknown. In this study, we investigated the GRNs by TFs and miRNAs with emphasis on breast cancer classifier genes at system level.