SLC6A14 and central nervous system cancer: The transport of majority extracellular amino acids relies on their membrane-bound transporters due to their hydrophilicity, and the expression of transporters is highly upregulated in many cancer types, such as Alanine-Serine-Cysteine Transporter 2 (ASCT2/SLC1A5) in triple negative breast cancer, prostate cancer and melanoma [37–39], LAT1 (SLC7A5) in endometrial cancer [40], ATB0,+ (SLC6A14) in colorectal cancer [41], xCT (SLC7A11) in glioma [42].