Notably, in light of the potential roles of sPD-L1 in regulating the interactions of PD-L1 with PD-1 (Fig. 4), the cancer cells were grown in culture for 24 h prior to the 4-hour co-culturing with PMBCs to allow the accumulation of sPD-L1 in cell supernatant. This evidence concerns the gene SPDL1 and cancer.