ASCT2 function may be particularly important because of its role in maintaining intracellular levels of glutamine, the main substrate for amino acid exchangers including System L. The importance of ASCT2 and glutamine transport has recently come to light with reports that elevated ASCT2 activity allows many cancers to escape the restriction of limited nutrient availability by increasing overall amino acid transport[47]. This evidence concerns the gene SLC1A5 and cancer.