Additionally, a LAT1-specific amino acid tracer, fluorine-18 (18F)-labeled α-methyl-L-tyrosine (18F-FAMT, Figure 1a), has shown specific accumulation in many types of malignant tumors, such as brain tumors, lung cancer, maxillofacial cancer, and thoracic cancer, in clinical practice [9,10]. The gene discussed is SLC7A5; the disease is cancer.