a, Representative immunofluorescence staining of SLC7A11 on paired colon cancer and adjacent normal tissues. H&E, haematoxylin and eosin (magnification, ×20). Numbers in the top left are specific tissue identification numbers of a normal/cancer tissue pair from one colon cancer patient. b, Tet-on p533KR cells were transfected with either control or plasmid overexpressing SLC7A11 followed by treatment as indicated. Quantification of cell death from two technical replicates is shown (mean ± s.d.). c, Western bot analysis of tet-on p533KR cells with or without SLC7A11 overexpression. VIN, vinculin. d, Xenograft tumours from tet-on p533KR cells shown in c. e, Tumour weight was determined (error bars, s.d. from from four tumours). Independent experiments were repeated three times and representative data are shown.