IHC staining of PD-L2 in tissue samples from primary gliomas WHO grade II-III patients (n = 20) and normal brain (n = 2) demonstrated that PD-L2 protein levels were more often increased in LGGs (WHO grade II-III) samples, while expression was low/undetectable in normal brain tissues (Figure 2). Taken together, these results indicated that PD-L2 levels were considerably higher in glioma tissue than in normal brain tissue. This evidence concerns the gene PDCD1LG2 and central nervous system cancer.