Biomarkers released by matrix metalloproteinase-mediated degradation of collagen have also been examined in AE-IPF; such a degradation product, versican, was found to be associated with mortality in a study of 68 patients with AE of idiopathic interstitial pneumonias, including 28 patients with AE-IPF [37]. This evidence concerns the gene VCAN and idiopathic pulmonary fibrosis.