STAT3 and cancer: In fact, by repressing the STAT3 pathway in in vitro and in vivo models, metformin inhibited cell proliferation and induced apoptosis and autophagy in a dose- and time-dependent manner in several cancer types, including esophageal squamous cell carcinoma, triple-negative breast cancer, endometrial, ovarian, bladder cancer, glioblastoma, chronic neutrophilic leukemia with mutated CSF3R, and cholangiocarcinoma [101,102,103,104,105,106,107].