This report, and recent findings on tumor immunity, suggest that systemic LAT1 inhibition in cancer patients is beneficial in terms of its anti-cancer effect by suppressing mTOR signaling, programmed cell death-1 ligand 1, expression, and cancer stemness, but is not beneficial through suppression of activated T-cells, which require increased amino acid uptake via LAT1 to maintain the T-cell activation state. The gene discussed is SLC7A5; the disease is cancer.