Xu B, Jungbluth AA, Frosina D, et al. - In 53 salivary duct carcinomas (SDC, an aggressive salivary malignancy that leads to high mortality rates and is frequently resistant to chemotherapy), the immunoexpression of programmed death ligand-1 (PD-L1), programmed death-1 (PD-1), major histocompatibility complex class I (MHC I) and preferentially expressed antigen in melanoma (PRAME) was assessed. In tumor cells (TCs) and immune cells (ICs), the immunoexpression levels of PD-L1, PD-1 in ICs, PRAME in TCs and MHC I in TCs were investigated and were associated with outcome. Alterations of the tumor immune microenvironment were common in SDCs, incorporating expression of PD-1/PD-L1 and PRAME, which clears the path to possible novel immune therapies, such as cancer vaccination, and PD-1/PD-L1 blockade, in these tumors.