STAT3 and breast cancer: In breast cancer, IL-6, secreted from CAFs, induced tamoxifen resistance by activating the Janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3) and phosphatidylinositol 3-kinase/AKT serine/threonine kinase (PI3K/AKT) pathways, resulting in the upregulation of E3 ubiquitin ligase anaphase-promoting complex 10 activity, which targeted estrogen receptor (ER)-α degradation through the ubiquitin-proteasome pathway [36].