SLC43A1 (LAT3) is a facilitated diffusion transporter mediating sodium-independent, electroneutral uptake of branched-chain and neutral amino acids including L-leucine, L-isoleucine, L-valine, and L-phenylalanine 1. The transporter functions as a uniporter without requiring ion gradients 1. Mechanistically, SLC43A1 operates within a feedforward regulatory loop with oncogenic MYC and SLC7A5, wherein MYC directly activates SLC43A1 transcription via E-box elements to enhance essential amino acid import 2. Elevated amino acid availability subsequently stimulates MYC translation through attenuation of the GCN2-eIF2α-ATF4 stress response pathway 2. In prostate cancer, SLC43A1 expression is androgen receptor-regulated, with dihydrotestosterone increasing and bicalutamide decreasing its expression 3. SLC43A1 demonstrates significant disease relevance across multiple malignancies. It was identified among the top ten metastasis-related genes correlated with gastric cancer prognosis 4 and as a potential colorectal cancer biomarker 5. In prostate cancer, high LAT3 expression independently predicts recurrence-free survival and correlates with advanced pathological stage 3. Functionally, SLC43A1 knockdown inhibits cancer cell proliferation, migration, and invasion while suppressing mTORC1 signaling 3. Additionally, SLC43A1 methylation variants associate with alcohol consumption and alcohol use disorder pathophysiology 6.