CD274 and glioma: Since tumor-associated DNA methylation is a key epigenetic alteration that manipulates gene expression patterns which, in turn, can aid in tumor progression (Das and Singal, 2004; Ehrlich, 2009), we evaluated the DNA methylation profile of PD-L1 in primary LGGs and GBMs using normal brain tissues as controls to determine if there are glioma-specific DNA hyper- or hypo-methylation resulting in gene expression modulation.