Study of LAT-1 expression and of ¹⁸F-FDOPA uptake in brain tumours. Illustration by a series of cases

Introduction. - PET imaging of amino acid analogues, in particular with F-18-FDOPA, is increasingly used for the diagnosis and post-therapeutic evaluation of brain tumors. The mechanism of F-18-FDOPA uptake in brain tumors is still debated in the literature, the main hypothesis being uptake via L-amino-transporter 1 (LAT-1). Method. - We present 4 cases of patients with primary or secondary brain lesions who underwent F-18-FDOPA PET/CT or PET/MRI for the evaluation of suspected tumor recurrence and who underwent surgical removal with immunostaining labeling of LAT-1 transporters within 3 months. For each of these patients, a correspondence between semi-quantitative PET parameters (SUVmax, TBRmax and TSRmax) and anatomopathological characteristics was performed. Results. - All patients had a significant and intense tumor uptake on F-18-FDOPA PET. In contrast, the expression level of LAT-1 receptors was very variable from one patient to another (LAT-1 score ranging from 0 to 193). Conclusion. - This article reflects the persistent questioning of the link between the LAT-1 receptor and the uptake intensity on F-18-FDOPA PET, especially in patients who have received a first line of treatment. (c) 2023 Elsevier Masson SAS. All rights reserved.