GLI1 and familial pancreatic carcinoma: However, IGF2 has been reported to be an important islet cell hormone in endocrine islet cells, which are dispersed throughout the exocrine pancreas that could act via a proxicrine mechanism on pancreatic cancer cells,[40, 41] so it could not be excluded soundly that the upregulation of IGFBP6 by Gli1 may only be a response of pancreatic cancer cells to the stimulus of paracrine IGF2 from islet cells.