@article {Kircher348, author = {Stefan Kircher and Antje Stolzenburg and Klaus Martin Kort{\"u}m and Malte Kircher and Matteo Da Via and Samuel Samnick and Andreas K. Buck and Hermann Einsele and Andreas Rosenwald and Constantin Lapa}, title = {Hexokinase-2 Expression in 11C-Methionine{\textendash}Positive, 18F-FDG{\textendash}Negative Multiple Myeloma}, volume = {60}, number = {3}, pages = {348--352}, year = {2019}, doi = {10.2967/jnumed.118.217539}, publisher = {Society of Nuclear Medicine}, abstract = {PET with 18F-FDG is the standard modality in nuclear medicine for imaging multiple myeloma (MM). However, viable MM as detected by MRI or PET with other metabolic tracers, including 11C-methionine, may be missed{\textemdash}for example, because of low hexokinase 2 (HK2) expression of tumor cells. The aim of this study was to further investigate potential reasons for PET false negativity. Methods: A cohort of 15 mainly pretreated patients with relapsed or refractory biopsy-proven, serologically active MM who underwent both 18F-FDG and 11C-methionine PET/CT was retrospectively analyzed. Results: In 9 of the 15 patients, 18F-FDG PET was negative in the presence of viable disease. In the remaining 6 patients, both 18F-FDG and 11C-methionine PET/CT revealed the same number of MM lesions. At immunohistochemistry, 18F-FDG{\textendash}negative myeloma did not exhibit significant differences in HK2 or glucose-6-phosphatase expression from 18F-FDG{\textendash}positive disease (P = 0.57 and P = 0.44, respectively). Conclusion: Beyond HK2 expression, 18F-FDG negativity in (mainly pretreated) MM patients seems to be associated with additional causes not yet known.}, issn = {0161-5505}, URL = {https://jnm.snmjournals.org/content/60/3/348}, eprint = {https://jnm.snmjournals.org/content/60/3/348.full.pdf}, journal = {Journal of Nuclear Medicine} }