SLC7A9 and cancer: Studies on amino acid transporters in cancer have so far mainly focused on glutamine transport mediated by ATB0,+ (30) as well as the exclusive neutral amino acid transporters ASCT2 (SLC1A5) (31, 32) and LAT1 (SLC7A5) (33) showing a dependence of cancer cell growth on transporter-mediated amino acid uptake.