The uptake of Gln from the extracellular environment into cells, including tumor cells, is mediated via the plasma membrane transporters such as alanine, serine, cysteine-preferring transporter 2 (ASCT2), a Na+-dependent neutral amino acid transporter encoded by solute-linked carrier family A1 member 5 (SLC1A5) [14,16]. Here, SLC1A5 is linked to neoplasm.