In a study on NKTCL (natural killer/T-cell lymphoma), patients with a high concentration of serum sPD-L1 (≥3.4 ng/ml) or with a high percentage of PD-L1 expression in tumor specimens (≥38%) responded poorly to treatment and exhibited markedly worse survival than patients with lower concentrations or lower percentages of expression. Here, SPDL1 is linked to neoplasm.