SLC7A11 and cancer: Interestingly, although biosynthesis of GS and HT requires cysteine as a substrate13,14, HT, but not GS, in cancer cells serves as a robust CD44/xCT-independent anti-oxidant that is rapidly converted to taurine, and compensates for the decreased capacity of cancer to attenuate oxidative stress during CD44-knockdown-induced GS suppression.