Fig. 1. Histological features of pancreatic adenocarcinoma and pancreatic intraepithelial neoplasias (PanINs). PanINs are graded according to degrees of cellular atypia. Pancreatic adenocarcinoma without PanIN (non-PanIN) (A), PanIN 1 (B), PanIN 2 (C), and PanIN 3 (D). H&E stain, ×500.