When considering the immune-suppressive nature of PD-L1, it was not surprising to note that this marker was associated with a poor prognosis in breast, bladder and non-small cell lung cancer as well as in malignant pleural mesothelioma and renal cell carcinoma, whereas the opposite prognosis was observed in breast cancer and HKSCC. Here, CD274 is linked to malignant pleural mesothelioma.