Although L1 amino acid transporter (LAT1) is reported to mediate the uptake of O-(2-18F-fluoroethyl)-L-tyrosine (18F-FET) into tumour cells, the levels of LAT1 expression do not correlate with the levels of 18F-FET uptake in idh mutant HGG. In particular, the lack of tracer uptake in 18F-FET-negative HGG cannot be explained by a reduced LAT1 expression. Here, IDH1 is linked to neoplasm.