SLC38A1 and neoplasm: However, although SLC1A5 is the major glutamine transporter, with high affinity and high capacity observed in many cancer types (24, 25), other members of the solute carrier superfamily including SLC7A5 (LAT1) and SLC38A1/2 (SNAT1/2) have also been linked to tumor-specific glutamine uptake (26).