The expression of ataxia-telangiectasia mutated protein, DNA dependent protein kinase protein and YKL-40 in primary central nervous system lymphoma

Abstract

Primary central nervous system (PCNS) diffuse large B-cell lymphoma (PCNS DLBCL) is a DLBCL with tropism for the central nervous system (CNS) microenvironment. Several studies to demonstrate biologic differences between PCNS-DLBCLs and non-CNS DLBCLs have been reported. In this study, we evaluated the differences between PCNS DLBCLs and non-CNS DLBCLs by application of immunohistochemical staining for ataxia-telangiectasia mutated gene (ATM), DNA-dependent protein kinase catalytic subunit (DNA-PKcs), Ku protein and YKL-40 using 27 cases of PCNS DLBCL and 29 cases of non-CNS DLBCL. Promoter methylation patterns of ATM were also analyzed by application of ATM gene promoter hypermethylation PCR. The differences in the tissue protein expression of ATM between PCNS DLBCL and non-CNS DLBCLs and the correlation between ATM protein expression and ATM gene promoter hypermethylation status were not demonstrated. The correlations between expression of ATM expression and loss of DNA-PKcs (p = 0.03) and between expression of ATM and loss of Ku80 PKcs (p = 0.04) were present only in PCNS DLBCLs. There were no significant difference in tissue expression of YKL-40 between PCNS DLBCLs and non-CNS DLBCLs. Although there were no differences in ATM protein expression and ATM gene promoter hypermethylation, this study showed the relations between ATM and DNA-PKcs and between ATM and Ku80 in PCNS DLBCLs. In this respect, more study is needed about the relations between ATM protein expression and DNA-PK protein expression in CNS DLBCLs and prognostic analysis between PCNS DLBCLs and non-CNS DLBCLs according to the study demonstrating the loss of Ku70, Ku80 and DNA-PKcs is more significant in high-grade lymphomas.