CD274 and prostate cancer: In regard to the role of plasma cells, a few studies reported that plasma cells had an immunosuppressive role in prostatic cancers, also in keeping with our results; IgA+ plasma cells within tumors induced CD8+ cell exhaustion and suppressed anti-tumor cytotoxic T cell responses through PD-L1 and IL-10, either of which could result in anergy or exhaustion [15-17].