HLA-C and primary central nervous system lymphoma: M18, M21, M7, M35, M25, M37, M40, and M36 are most significantly enriched for MHC protein complex, neutrophil degranulation, regulation of immune effector process, response to virus, B cell activation, IgG binding, pattern recognition receptor activity, acute inflammatory response, respectively, suggesting that immune response plays a crucial role in the pathophysiological processes of PCNSL.