STAT3 and breast carcinoma: Furthermore, we analysed mRNA data of The Cancer Genome Atlas (TCGA) breast cancer cohorts and found that HIF1A expression was significantly overexpressed in 1215 breast cancer specimens compared to 113 non‐tumour tissues (Figure 1C) and positive correlations were observed between HIF1A and STAT3 (Figure 1D) (r = 0.1998, P < .0001).