SLC7A11 and neoplasm: On the other hand, Conrad and colleagues recently reported (based on in vitro cell culture experiments) that sorafenib did not trigger ferroptosis in a panel of cancer cell lines, and that despite abundant expression of SLC7A11 (the substrate-specific subunit of system xc−), classic system xc− inhibitors (e.g., erastin) could only induce ferroptotic cell death in a subset of tumor cell lines80.