TGFB1 and idiopathic pulmonary fibrosis: In a recent study by Minagawa et al. [72], β-gal-positive senescent epithelial cells and increased levels of p21 were demonstrated in lung biopsies of IPF patients, and also established, in vitro, that TGFβ plays a pivotal role in inducing lung epithelial cell senescence, and that the DNA repair specific sirtuin (SIRT), SIRT6 inhibited TGFβ-induced senescence.