TNF and pulmonary fibrosis: For example, in idiopathic pulmonary fibrosis, a variety of factors can stimulate their differentiation into myofibroblasts including tumor necrosis factor-α (TNF-(α), transforming growth factor-β1 (TGF-β1), endoplasmic reticulum (ER) stress, Hedgehog (HH), and Wingless/integrated (Wnt) signaling.