CCND1 and pancreatic insulinoma: These findings indicate that IL-22 affects the secretion of secretory proteins other than MUC2, particularly the regenerating islet-derived 3 family antimicrobial peptides REG3α and REG3γ. Although these peptides help in maintaining barrier integrity, overexpression of REG3α has been found to promote insulinoma cell growth through increases in cyclin D1 and CDK4 levels [56], where REG3γ promotes β cell regeneration in type I diabetic mice [57].