IL6 and cancer: Indeed, TAMs actively support the expansion of cancer stem cells by secreting a plethora of mediators, such as interleukin-6 (IL-6), platelet-derived growth factor (PDGF), milk fat globule-EGF factor 8 (MFG-E8), human cationic antimicrobial protein-18/LL-37 (hCAP-18/LL-37), and the recently implicated glycoprotein non-metastatic B (GPNMB) [43,44,45,46].