BCL2 and diffuse large B-cell lymphoma: It is well known that PCNS-DLBCL has a variety of molecular characteristics, and the primary factors closely related to prognosis are BCL-2/MYC double expression, BCL-2/C-MYC double aberrations (17), and BCL-6 rearrangements, which are often recognized using cytogenetic fluorescence in situ hybridization (FISH) studies (18).