As a point of convergence for many oncogenic signaling pathways, the transcription factor signal transducer and activator of transcription 3 (STAT3) is involved in cell growth through the downstream signaling molecules such as BCL-2 and cyclin D1.9, 10, 11 Recent studies have declared that STAT3 is activated in many tumors such as breast cancer, ovarian cancer, lung cancer and so on.12, 13, 14 STAT3 has become a promising target of cancer treatment.15 Here, STAT3 is linked to breast cancer.