SLC1A5 and cancer: Besides, an important feature of the ASCT2 transport is that both transported AAs—glutamine and serine—are fundamental for the “redox code” of the cancer cell: serine-driven one-carbon metabolism aka folate cycle provides the cell with necessary reducing equivalents (NADPH) (Figure 2), while ASCT2-driven glutamine uptake fuels xCT-dependent import of the redox-active AA cysteine (explained extensively later (Figure 2) [53]).