PDCD1LG2 and neoplasm: Since the results above showed that S100A14 was mainly expressed in tumor cells, and previous studies had proved that S100 family proteins might up-regulate the expression of PD-L1 [32, 48], we hypothesized that S100A14 might be related to the dysregulation of immune checkpoints including PD-L1 and PD-L2, which had been widely acknowledged to inhibit T cell activation through activation of PD-1 receptors [49–51].