CDKN1A and idiopathic interstitial pneumonia: Hence, it has been shown that the epithelial cells from IPF lungs strongly expressed cellular senescence markers p16 and p21 together with an increased secretion of SASP factors as insulin growth factor binding proteins (Igfbp) 3, 4 and 7 and MMP 3, 12 and 14 (Lehmann et al., 2017).