Imaging of tumor glucose utilization with positron emission tomography.

In recent years, imaging of tumor glucose metabolism with positron emission tomography and fluorodeoxyglucose (FDG-PET) has become a routine test for detection, staging and restaging of malignant lymphomas and many solid tumors. FDG-PET is also increasingly used to monitor the effects of chemotherapy. The success of FDG-PET in oncologic imaging has generated considerable interest in understanding the molecular mechanisms underlying the markedly accelerated glucose use of almost all human cancers. Recent studies have indicated that there may be a close relation between the activation of oncogenic signaling pathways and cellular glucose utilization. For example deregulation of Akt, ras and MYC as well as loss of p53 function have been reported to confer increased glucose metabolic rates in cancer cells. These findings suggest that imaging of tumor glucose utilization may represent a marker for the activity of oncogenic pathways and metabolic changes during therapy may be used as a readout for the effectiveness of drugs targeting these pathways. However, the mechanisms for increased glucose metabolic activity of cancers cells are multifactorial and clinical studies will be necessary to determine in which context imaging of tumor glucose metabolism may be used for treatment monitoring.