POSTN and idiopathic pulmonary fibrosis: Several serum biomarkers, such as Krebs von den Lungen-6 (KL-6) and surfactant proteins A and D (SP-A and -D, respectively), are clinically used for diagnosing AE-IPF [7, 8], but these markers are not adequately efficient; other biomarkers, such as monomeric periostin [9] and heat shock protein 47 (HSP47) [10], have also been recently reported as surrogate markers for detecting AE-IPF.