Δ40p53, which we have previously shown to localise in both the nucleus and cytoplasm in these cells [20], co-localised with Nanog, Sox2, and Oct4 (which are localised mainly in the nucleoplasm) in both breast cancer cell lines (Fig. 2A, B) (p < 0.05 for Nanog, Sox2, and Oct4 in MCF-7 and Nanog in ZR75-1). The gene discussed is POU5F1; the disease is breast cancer.