PROX1 and intestinal neoplasm: First, as also shown by the intracellular accumulation of active β-catenin, several targets and members of the Wnt signalling cascade are differentially expressed in the P3 signature including Lgr5, Mmp2 and Mmp7, Dkk2, Pla2g2a, Prox1, Sox17, T (brachyury), Wif1, and Fzd5. The presence of Lgr5 among the upregulated genes is of interest as it indicates that this well-known marker of normal cycling stem cells in the mouse intestine [21] might also represent a useful CSC marker in mouse intestinal tumours as recently demonstrated by lineage tracing [22].