L-type amino acid transporter (LAT) 1 expression in F-18-FET-negative gliomas

Vettermann, Franziska J. and Diekmann, Caroline and Weidner, Lorraine and Unterrainer, Marcus and Suchorska, Bogdana and Ruf, Viktoria and Dorostkar, Mario and Wenter, Vera and Herms, Jochen and Tonn, Jorg-Christian and Bartenstein, Peter and Riemenschneider, Markus J. and Albert, Nathalie L. (2021) L-type amino acid transporter (LAT) 1 expression in F-18-FET-negative gliomas. EJNMMI RESEARCH, 11 (1): 124. ISSN 2191-219X,

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Abstract

Background O-(2-[F-18]-fluoroethyl)-L-tyrosine (F-18-FET) is a highly sensitive PET tracer for glioma imaging, and its uptake is suggested to be driven by an overexpression of the L-type amino-acid transporter 1 (LAT1). However, 30% of low- and 5% of high-grade gliomas do not present enhanced F-18-FET uptake at primary diagnosis ("F-18-FET-negative gliomas") and the pathophysiologic basis for this phenomenon remains unclear. The aim of this study was to determine the expression of LAT1 in a homogeneous group of newly diagnosed F-18-FET-negative gliomas and to compare them to a matched group of F-18-FET-positive gliomas. Forty newly diagnosed IDH-mutant astrocytomas without 1p/19q codeletion were evaluated (n = 20 F-18-FET-negative (tumour-to-background ratio (TBR) < 1.6), n = 20 F-18-FET-positive gliomas (TBR > 1.6)). LAT1 immunohistochemistry (IHC) was performed using SLC7A5/LAT1 antibody. The percentage of LAT1-positive tumour cells (%) and the staining intensity (range 0-2) were multiplied to an overall score (H-score; range 0-200) and correlated to PET findings as well as progression-free survival (PFS). Results IHC staining of LAT1 expression was positive in both, F-18-FET-positive as well as F-18-FET-negative gliomas. No differences were found between the F-18-FET-negative and F-18-FET-positive group with regard to percentage of LAT1-positive tumour cells, staining intensity or H-score. Interestingly, the LAT1 expression showed a significant negative correlation with the PFS (p = 0.031), whereas no significant correlation was found for TBRmax, neither in the overall group nor in the F-18-FET-positive group only (p = 0.651 and p = 0.140). Conclusion Although LAT1 is reported to mediate the uptake of F-18-FET into tumour cells, the levels of LAT1 expression do not correlate with the levels of F-18-FET uptake in IDH-mutant astrocytomas. In particular, the lack of tracer uptake in F-18-FET-negative gliomas cannot be explained by a reduced LAT1 expression. A higher LAT1 expression in IDH-mutant astrocytomas seems to be associated with a short PFS. Further studies regarding mechanisms influencing the uptake of F-18-FET are necessary.

Item Type: Article
Uncontrolled Keywords: CENTRAL-NERVOUS-SYSTEM; DYNAMIC F-18-FET PET; LOW-GRADE GLIOMA; RESPONSE ASSESSMENT; PROGNOSTIC-SIGNIFICANCE; LUNG; C-11-METHIONINE; NEUROONCOLOGY; ADENOCARCINOMA; ASCT2; LAT1; FET PET; Glioma; Molecular imaging
Subjects: 600 Technology > 610 Medical sciences Medicine
Divisions: Medicine > Abteilung für Neuropathologie
Depositing User: Dr. Gernot Deinzer
Date Deposited: 20 Sep 2022 09:06
Last Modified: 20 Sep 2022 09:06
URI: https://pred.uni-regensburg.de/id/eprint/47638

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