SOX9 and pneumocystosis: In human craniopharyngiomas, which are composed mainly of non-endocrine cells, the expression of SOX2/SOX9 (both progenitor/stem cell markers) has been well documented in both the papillary type (PCP), harbouring MAPK pathway mutations as well as the adamantinomatous type (ACP) that harbour CTNNB1 mutations (encoding β-catenin) (Hölsken et al. 2014, Thimsen et al. 2017, Haston et al. 2017).