ASCT2 is an alanine-serine-cysteine amino acid transporter and solute linked carrier family 1 member A5 (SLC1A5). It functions as an essential high-affinity glutamine transporter. It also functions as a Na⁺-dependent transporter for alanine, serine and cysteine. The transport process is electroneutral which involves the Na⁺-coupled influx of glutamine to the Na⁺-coupled efflux of another substrate such as alanine, serine or cysteine. ASCT2 is expressed various peripheral tissues such as the lung and kidney^1,2. ASCT2 has an important contribution to the homeostasis of amino acid metabolism within tumor cells³.

ASCT2 seems to be up regulated in several cancerous tissues such as stomach, liver, kidney, breast, prostate, skin, colorectal, pancreatic, tongue and lung cancers. Studies have shown that ASCT2 is necessary for activating critical survival and cellular growth signaling cascades in cancer, which includes mTOR and ERK pathways.  It has been shown that knockdown of ASCT2 in prostate cancer cell line xenograft models significantly inhibit tumor growth and metastasis in vivo. Thus, ASCT2 is a potential cancer therapeutic target^1,2.