To examine cell type–specific expression of p300 in lung samples from patients with IPF and lung fibrosis mouse models, we performed coimmunofluorescence (co-IF) staining using antibodies against pro-surfactant protein C (pro-SPC, an ATII cell marker), club cell secretory protein (CCSP, a club cell marker), forkhead box J1 (FoxJ1, a ciliated cell marker), podoplanin (PDPN, an ATI cell marker), Mucin 5AC (Muc5AC, a goblet cell marker), and α-smooth muscle actin (α-SMA, a myofibroblast cell marker). Here, MUC5AC is linked to idiopathic interstitial pneumonia.