SLC7A11 and cancer: However, chronic lymphocytic leukemia cells are able to transport cysteine but not cystine [26], and pancreatic ductal adenocarcinoma (PDAC) cells transport cysteine to compensate for the intracellular cysteine pool once xCT/SLC7A11 is knocked out [27,28], suggesting that the underlying mechanisms of cysteine metabolism in various cancer types are different.