INS and pancreatic insulinoma: Our previous methylation mapping results of the mouse Ins2 promoter revealed three CpG dinucleotide sites that are located at positions −414, −182, and −171 bp relative to the transcription start site (TSS) and these CpG sites have a specific methylation pattern in insulin-producing pancreatic beta cells and NIT-1 mouse insulinoma cells compared to other tissues [21].