BMP6 and renal cell carcinoma: In renal cell carcinoma patients, the triple positivity for bone morphogenetic protein-6 (BMP-6, a member of the TGF-β superfamily) and CD68 as well as IL-10 positivity in biopsies was correlated with worse cumulative survival, indicating that BMP-6 induces M2 macrophage polarization with IL-10 production via activation of Smad5 and STAT3 [57].