The expression of type I procollagen and HSP47 was also significantly higher in type II pneumocytes identified in surgical biopsy specimens from patients with idiopathic usual interstitial pneumonia (UIP) than in those from patients with collagen vascular disease-associated UIP and idiopathic nonspecific interstitial pneumonia [26], which have better prognoses than idiopathic UIP [30]. Here, COL1A2 is linked to idiopathic pulmonary fibrosis.