TGFB1 and pulmonary emphysema: To further validate these findings, we cultured human lung fibroblasts with and without TGFβ1 and found that the set of genes most induced by TGFβ1 were enriched among genes that decrease in expression with increasing regional emphysema severity (FDR <0.05, GSEA; see Additional file 8 for the GSEA enrichment plot and Additional file 1 for the fibroblast culture methods).