Furthermore, western blot (WB) for pErk expression was performed using frozen specimens obtained from patients, which showed a high level of pErk expression in LC-IPF as compared to LC-non-IPF samples (n = 3 each), suggesting that cell proliferation signaling is more highly activated in tumors with IPF (Supplementary Fig. 1a, Supplementary Table 2). This evidence concerns the gene EIF2AK3 and idiopathic pulmonary fibrosis.