STAT3 and breast cancer: However, Scara5 promotes cellular iron uptake by binding serum ferritin, but the overexpression of Scara5 significantly suppresses breast cancer cell proliferation by inactivating the extracellular signal-regulated kinase1/2 (ERK1/2), signal transducer and activator of transcription 3 (STAT3), and serine/threonine kinase AKT signaling pathways [115].