Amino acid PET tracers, like 11C-methionine (MET), 18F-fluoroethyl-L-tyrosine (FET), and fluorodopa (FDOPA), are transported via the L amino acid transporter type 1 (LAT1) system which is expressed on glial cells, and its expression is directly proportional to grade of glioma [6]. The gene discussed is SLC7A5; the disease is central nervous system cancer.