Among the 30 AA transporters identified in human physiology, the L-type AA transporter 1 (LAT1/SLC7A5) and the alanine-serine-cysteine transporter 2 (ASCT2/SLC1A5) have emerged as major pro-tumoral transporters with increased expression levels correlating with poor patient prognosis in a large number of cancer types (13, –, 16). Here, SLC7A5 is linked to cancer.