STAT3 and breast cancer: Studies have shown that miR-26a acts as a tumor suppressor in lung cancer, breast cancer, HCC, rhabdomyosarcoma, prostate cancer, melanoma, papillary thyroid carcinoma, gastrointestinal carcinomas through its action on key proteins involved in the control of cell proliferation such as p53, SMAD1, EZH2, IL-6-Stat3, CTDSP1/2/L, SODD, CKS2, FGF9.