STAT3 and breast cancer: Notably, the CypA/CD147 axis plays an important role in the initiation, growth, and survival of CSCs by upregulating major signaling pathways, including Wnt/β-catenin, STAT3, Notch, phosphatidylinositol 3-kinase (PI3K)/AKT, MAPK, and nuclear factor kappa B (NF-κB), in several cancers, such as glioma, colon cancer, pancreatic cancer, and breast cancer [13,41,42,43,44].