In rat insulinoma-m5F cells under glucose-induced toxicity, treatment of flavan-3-ols led to improvement in the insulin secretory function and viability of β-cells through increased expression of insulin receptor substrate 2 (IRS2), AKT, forkhead box protein O1 (FOXO1), and pancreatic duodenal homeobox-1 (PDX-1) [191]. This evidence concerns the gene PDX1 and pancreatic insulinoma.