Related reports had revealed that STAT3 expressions were associated with prognosis of diverse types of tumours such as breast cancer, acute myelogenous leukaemia and glioma, among others.38, 39, 40 Previously, a few studies had reported the overexpression of STAT3 in certain cancer types including intrahepatic cholangiocarcinoma, breast cancer and high‐grade glioma.18, 41, 42 Additionally, Carro et al43 reported a relationship between STAT3 expression and the mesenchymal transformation of glioma, suggesting that STAT3 was a “master regulator” of glioma transformation. This evidence concerns the gene STAT3 and breast cancer.