IGFBP1 and idiopathic pulmonary fibrosis: Until now, several studies have demonstrated that MMP7 is a valuable biomarker for IPF alone, or in combination with other candidate biomarkers, such as MMP1, MPP8, IGFBP1, TNF SP-A, SP-D or KL-6 [5,6,45,46], but not for CTD-ILD.