GPT and neoplasm: Interestingly, enrichment of DAXX/ATRX loss and MEN1 mutations in tumours positive for ARX suggest that α cells are more susceptible to these mutations while β cells have a peculiar mutations spectrum including YY1, pointing out the difference between non functioning PanNET and insulinoma.9 Only malignant insulinoma showed positivity for ARX and ALT, suggesting a similar development to non-functioning tumours.10