CD274 and cancer: In addition, different myeloid cells in the cancer microenvironment, e.g., myeloid-derived suppressor cells, tumor-associated macrophages, and dendritic cells, have been reported to express high levels of LRRC33 and thus to be the major sources of TGF-β144, whose immunosuppressive function contributes to tumor progression and leads to failure in anti-PD-1/PD-L1 therapies in certain types of cancer45.