Objective To detect the expressions of chemokine receptor CXCR5 and its ligands-chemokine CXCL13-in primary central nervous system lymphoma(PCNSL)and their possible role in the occurrence and development of this disease.Methods Applying immunohistochemical and reverse transcription polymerase chain reaction(RT-PCR),the expressions of CXCR5 and CXCL13in five cases of PCNSL and 10 cases of normal brain tissue were detected. Results Immunohistochemistry indicated that the expressions of CXCR5 and CXCL13in tumo...