ACE2 and pancreatic insulinoma: Both HNF1α or HNF1β bind to the − 346 to − 330 bp (5′-GTATCTTTAACAGCTTT-3′), − 329 to − 312 bp (5′-CTAGGAAAATATTAACCA-3′), and − 259 to − 242 bp (5′-AGGATTAAAGAATAACGT-3′) regions upstream of the ACE2 gene transcriptional start site (Fig. 2, Table 1), resulting in the induction of ACE2 transcription in mouse islet cells and rat insulinoma cells [34].