CD169-positive sinus macrophages in the lymph nodes determine bladder cancer prognosis.

CD169(+) macrophages are suggested to play a pivotal role in establishing anti-tumor immunity. They capture dead tumor cell-associated antigens and transfer their information to lymphocsytes, including CD8(+) T cells, which is important for successful tumor suppression. This study aimed to determine the prognostic significance of CD169(+) macrophages residing in the tumor-draining lymph nodes from cases of bladder cancer. In this retrospective study, 44 bladder cancer patients who received radical cystectomy were examined. The abundance of CD169(+) macrophages in the regional lymph nodes and the number of CD8(+) T cells in the primary tumor were investigated by immunohistochemistry. A CD169 score was calculated based on the intensity of CD169 staining and the proportion of CD169(+) macrophages, and the scores were compared to the patients' clinicopathological parameters. A high CD169 score was significantly associated with low T stage and with a high number of CD8(+) T cells infiltrating into the tumor. The group with high CD169 expression had significantly longer cancer-specific survival than the group with low CD169 expression (5-year cancer-specific survival rate: 83.3% vs 31.3%). In a multivariate analysis, the CD169 score was identified as a strong and independent favorable prognostic factor for cancer-specific survival. Our findings suggest that CD169(+) macrophages in the lymph nodes enhance anti-tumor immunity by expanding CD8(+) T cells in bladder cancer. The CD169 score may serve as a novel marker for the evaluation of bladder cancer prognosis.