SPDL1 and chordoma: conducted ELISA detection for soluble PD-1 (sPD-1), soluble PD-L1 (sPD-L1) and soluble VISTA (sVISTA) in the peripheral blood of chordoma patients and found that there were higher expression of sPD-L1 and lower expression of sVISTA in chordoma patient than in control, no matter the tumor location, stage, tumor type, patient age and gender (46, 47), suggesting that chordoma could affect the expression of soluble immune checkpoints and might affect the immune status of the whole body.