The reduced expression of β cell transcription factors, such as Pdx1 (pancreatic and duodenal homeobox 1) and MafA (V-Maf avian musculoaponeurotic fibrosarcoma oncogene homolog A), allude to a loss of β cell identity, a characteristic of ER-stressed T2D islets (40). Here, PDX1 is linked to type 2 diabetes mellitus.