Tumour xenografts with high levels of Δ40p53 also showed increased Sox2 and Ki67 expression when compared to LeGO tumours (Fig. 6), highlighting the self-renewal properties of cells with overexpressed Δ40p53 and underpinning the association of Δ40p53 with worse outcomes [6, 11]. This evidence concerns the gene MKI67 and neoplasm.