However, previous studies have suggested that biomarkers, such as Krebs von den lungen-6 [8], surfactant protein-A (SP-A) [9], CC chemokine ligand 18 [10], and matrix metalloproteinase (MMP)-7 [11], may serve as prognostic biomarkers for IPF. This evidence concerns the gene MMP7 and idiopathic pulmonary fibrosis.