STAT3 and breast cancer: To be more specific, IL-6 has been demonstrated to be responsible for VEGF-dependent angiogenesis in cervical cancer (23); IL-6–activated STAT3 helps cell survival and promotes cell proliferation during colitis-induced tumorigenesis of gastrointestinal cancer (24); IL-6-induced epithelial-mesenchymal transition (EMT) is critical for the metastasis of breast cancer (25) and head and neck cancers (26).