VSIR and neoplasm: (51) found that the ectopic expression of VISTA drives the phenotypic shift of monocytes to M2 macrophages, down-regulates the signal regulatory protein alpha (SIRPα), reduces the IL-1β levels and increases the anti-inflammatory cytokine IL-10 levels, thereby resulting in an immunosuppressive microenvironment and promoting tumor progression in vitro (52).