PDX1 and type 2 diabetes mellitus: Also in the adult human pancreas, maintenance of beta cell identity is associated with the presence of key transcription factors (in particular PDX1, FOXO1, MAFA, NKX6.1), and changes in their expression and/or localization have been described in the islets from type 2 diabetic (T2D) individuals, contributing to beta cell de-differentiation (i.e., the regression to a progenitor-like state) in this disease (Talchai et al., 2012; Guo et al., 2013; Kitamura, 2013; Rutter et al., 2015; Spijker et al., 2015; Cinti et al., 2016; Remedi and Emfinger, 2016).