While SHM/CSR also occurs in most DLBCLs (explaining the discordance between percentage of MIB-1-positive and TK-1-positive cells in most DLBCL in our study), the relative contribution of DNA repair to 18 F-FLT uptake in DLBCL is apparently small in most cases, so that a significant correlation between percentage of MIB-1-positive cells and 18 F-FLT uptake can be found. This evidence concerns the gene TK1 and diffuse large B-cell lymphoma.