Cancer-driven granulo-monocytopoiesis stimulates expansion of tumor promoting 
myeloid populations, mostly myeloid-derived suppressor cells (MDSCs) and 
tumor-associated macrophages (TAMs). We identified subsets of MDSCs and TAMs 
based on the expression of retinoic-acid-related orphan receptor (RORC1/RORγ) in 
human and mouse tumor bearers. RORC1 orchestrates myelopoiesis by suppressing 
negative (Socs3 and Bcl3) and promoting positive (C/EBPβ) regulators of 
granulopoiesis, as well as the key transcriptional mediators of myeloid 
progenitor commitment and differentiation to the monocytic/macrophage lineage 
(IRF8 and PU.1). RORC1 supported tumor-promoting innate immunity by protecting 
MDSCs from apoptosis, mediating TAM differentiation and M2 polarization, and 
limiting tumor infiltration by mature neutrophils. Accordingly, ablation of 
RORC1 in the hematopoietic compartment prevented cancer-driven myelopoiesis, 
resulting in inhibition of tumor growth and metastasis.