STAT3 and breast cancer: CAFs also supporting their metabolism and BC metabolism by several metabolic proteins (STAT-1, STAT-3, HIF-1α, GLUT-1, alpha-ketoglutarate (α-KG), COX-2, and PKM2), and other oncogenic proteins such as PGE2, TGF-1β, FOS-like 2 (FOSL-2), and clusterin.