NKX6-1 and diabetes mellitus: We also assessed insulin-positive cells immunoreactive for nuclear V-maf musculoaponeurotic fibrosarcoma oncogene homolog A (MAFA) and NK homeobox, family 6, member A (NKX6.1), in a subset of subjects and found similar declines in early- and advanced-DM (Supplemental Figure 2, B, C, E, and F).