In breast cancer, HMGB1 enhances tumor stem cell self‐renewal capacity and promotes tumorigenesis and metastasis by activating TLR2, inducing IκBα phosphorylation, stimulating IL‐6 and TGF‐β secretion, and activating STAT3 and Smad3 signaling pathways. This evidence concerns the gene HMGB1 and breast carcinoma.