TAS1R1 and neoplasm: Amino acid metabolism activates mTORC1 either through binding at the taste-1-receptor member 1 (T1R1) and taste 1 receptor member 3 (T1R3) hetero-dimer cell-surface G-protein-coupled receptors, as a luminal sensor of amino acids extracellularly [124], or the amino acids transported across the tumor cell membrane into the epithelium for intracellular binding to their specific binding site on the regulator-Rag complex, except for cytoplasmic methionine, which has to be converted to SAM to bind to the SAMTOR/GATOR1 regulator protein complex to activate mTORC1 [122,125].