SPDL1 and breast cancer: Here, to investigate sPD-L1 as a soluble form of PD-L1 in immune suppression, we retrospectively evaluated the level of sPD-L1 in the blood plasma of IBCa patients and analyzed the relationship of sPD-L1 expression with the presence of Bregs; clinical characteristics including TNM stage, tumor grade, lymph node infiltration; and the presence of metastases as well as the antitumor activity of T cells in breast cancer and lymphocyte coculture systems.