Likewise, a significant increase in bihormonal insulin+/glucagon+ and NKX6.1+/amyloid+/glucagon+ cells was found upon analysis of mature β cell markers (e.g., MAFA, FOXO1, NKX6.1) in T2D human and nonhuman primate pancreas [10]; a greater frequency of Nkx6.1+ glucagon+ insulin− cells was found in islet amyloid-positive regions. This evidence concerns the gene NKX6-1 and type 2 diabetes mellitus.