TNF and neoplasm: Resident fibroblasts, especially PSC, have the ability to transdifferentiate from a “quiescent” retinoid/lipid storing phenotype in the normal pancreas to an “activated” α-smooth muscle-actin-producing myofibroblastic phenotype through tumor-derived stimuli such as cytokines (interleukin(IL)-1, IL-6, and IL-8 and tumor necrosis factor (TNF)-α), growth factors (platelet-derived growth factor (PDGF) and tumor growth factor (TGF)-β), and reactive oxygen species [33].