TGFB1 and colonic neoplasm: Elevated expression of PRNP in homozygous mice (Additional file 1: Fig. S4A) was accompanied by increased expression of a set of genes that we previously identified as PrPC gene targets in colon cancer cells [10], namely App, Bace1, Dkk3, Pdgfc and Tgfb1 (Additional file 1: Fig. S4B–F), thus validating our model as a robust PRNP-overexpressing paradigm.