STAT3 and cancer: JAK2/STAT3 signaling pathway is widely demonstrated to highly abnormally activate in various cancers, for example, pancreatic cancer [16, 17], gastric cancer [18, 19], breast cancer [20–22], liver cancer [23–25], colorectal cancer [26, 27], colon cancer [28, 29], ovarian cancer [30, 31], lung cancer [32–34].