Calculation of a high composite FAO gene score revealed that the expression of FAO genes decreased from healthy old to IPF lungs in AT2, AT2 transitional, RAS (SCGB1A1+SCGB3A2+SFTPB+, low SPC), and secretory (SCGB1A1+SCGB3A2+SFTPC–) cell populations in IPF lungs in comparison with healthy old lungs (Figure 1C and Supplemental Table 3). This evidence concerns the gene SCGB1A1 and idiopathic pulmonary fibrosis.