SOX2 and pituitary tumor: We sought to investigate whether a similar mechanism may underlie the development of pituitary tumours in Hesx1Cre/+;Ctnnb1lox(ex3)/+;R26YFP/+ mice, another model for human ACP, in which oncogenic β-catenin is expressed in the embryonic pituitary precursors that normally give rise to all the cell lineages of the mature pituitary gland, including Sox2+ stem cells27.