Despite the wide range of LAT1 applicationswith high expectationsfor drug delivery to the CNS and in cancer therapy, there are stillgaps in our knowledge of the structural features which distinguisha LAT1 substrate from an inhibitor.14 Ourgroup has broad experience in LAT1-targeted drug discovery, and ourprevious studies have led to the development of the three-dimensional(3D) pharmacophore15 and quantitative structure–activityrelationship models.16 These studies havehighlighted some structural features responsible for efficient LAT1binding. This evidence concerns the gene SLC7A5 and cancer.