ARG1 and familial pancreatic carcinoma: In the pancreatic cancer model, blockade of CSF1R signaling significantly reduces the number of TAM in the tumor as well as mRNA expression of immunosuppressive molecules such as PD-L2, transforming growth factor-β (TGF-β), and arginase-1 (ARG1) in the remaining TAM (Zhu et al., 2014), suggesting that CSF1R inhibition improves checkpoint therapies not only by depletion of TAM but also by reducing their expression of suppressive molecules.