CTSE and idiopathic pulmonary fibrosis: The expression of the selected genes, which includes the fibrosis-associated genes MMP7 (36) and SERPINE1 (37) and SEMA7A and CTSE, previously shown to be up-regulated in primary AEC2 isolated from IPF patients (5) (Fig 2F), mostly mapped to the ABI and basal cell clusters (Figs 5D and S9B).