To further explore the molecular mechanisms underlying malignant cell lineages in BRCA metastasis, biological characteristics and expression levels of 50 cancer‐related hallmark signalling pathways were illustrated in the heat map, which revealed that most of the DEGs were significantly enriched in the following hallmark signalling pathways: hallmark pancreas β cells, hallmark WNT‐β catenin signalling, hallmark epithelial mesenchymal transition, hallmark IL6 JAK STAT3 signalling and hallmark angiogenesis (Figure 2H). This evidence concerns the gene STAT3 and cancer.