PTGS2 and pulmonary fibrosis: Here, we used comparative expression analysis to identify apoptosis-linked genes, including midikine, gremlin1, Spp1,Ptgs2, Bak, Bax, Bcl2, and Fas, in IPF and a mouse model of TGFα-induced pulmonary fibrosis and validated changes in their expression by RT-PCR and found a significant overlap.