Decreased ING4 expression within IPF lung compared to COP and normal lung. (A) Representative immunohistochemistry with an anti-ING4 antibody on lung paraffin sections from IPF and COP patients as well as control (CTRL) subjects. ING4 was extensively expressed in normal alveolar epithelial and endothelial cells in control lung samples and was also visualized in alveolar epithelial cells surrounding areas of active fibrosis, called Masson bodies, within COP lung. On the contrary, ING4 was almost absent in alveolar epithelium and fibrotic interstitium (fibroblastic foci) within IPF lung. (B) Computerized image analysis of immunostained sections. *p < 0.05, **p < 0.005, ***p < 0.001 (One way ANOVA and unpaired t-test with Bonferroni correction, F = 171,126).