@article{WondergemHerrmannSyrbuetal.2014, author = {Wondergem, Marielle J. and Herrmann, Ken and Syrbu, Sergei and Zijlstra, Jos{\´e}e M. and Hoetjes, Nikie and Hoekstra, Otto S. and Cillessen, Saskia A. G. M. and Moesbergen, Laura M. and Buck, Andreas K. and Vose, Julie M. and Juweid, Malik E.}, title = {18 F-fluorothymidine uptake in follicular lymphoma and error-prone DNA repair}, series = {EJNMMI Research}, volume = {4}, journal = {EJNMMI Research}, doi = {10.1186/2191-219x-4-3}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-121233}, pages = {3}, year = {2014}, abstract = {BACKGROUND: We observed a disproportional 18 F-fluorothymidine (F-FLT) uptake in follicular lymphoma (FL) relative to its low cell proliferation. We tested the hypothesis that the 'excess' uptake of 18 F-FLT in FL is related to error-prone DNA repair and investigated whether this also contributes to 18 F-FLT uptake in diffuse large B cell lymphoma (DLBCL). METHODS: We performed immunohistochemical stainings to assess the pure DNA replication marker MIB-1 as well as markers of both DNA replication and repair like PCNA, TK-1 and RPA1 on lymph node biopsies of 27 FLs and 35 DLBCLs. In 7 FL and 15 DLBCL patients, 18 F-FLT-PET had been performed. RESULTS: 18 F-FLT uptake was lower in FL than in DLBCL (median SUVmax 5.7 vs. 8.9, p = 0,004), but the ratio of 18 F-FLT-SUVmax to percentage of MIB-1 positive cells was significantly higher in FL compared with DLBCL (p = 0.001). The median percentage of MIB-1 positive cells was 10\% (range, 10\% to 20\%) in FL and 70\% (40\% to 80\%) in DLBCL. In contrast, the median percentages of PCNA, TK-1 and RPA1 positive cells were 90\% (range, 80 to 100), 90\% (80 to 100) and 100\% (80 to 100) in FL versus 90\% (60 to 100), 90\% (60 to 100) and 100\% (80 to 100) in DLBCL, respectively. CONCLUSIONS: This is the first demonstration of a striking discordance between 18 F-FLT uptake in FL and tumour cell proliferation. High expression of DNA replication and repair markers compared with the pure proliferation marker MIB-1 in FL suggests that this discordance might be due to error-prone DNA repair. While DNA repair-related 18 F-FLT uptake considerably contributes to 18 F-FLT uptake in FL, its contribution to 18 F-FLT uptake in highly proliferative DLBCL is small. This apparently high contribution of DNA repair to the 18 F-FLT signal in FL may hamper studies where 18 F-FLT is used to assess response to cytostatic therapy or to distinguish between FL and transformed lymphoma.}, language = {en} }