TGFB1 and chronic obstructive pulmonary disease: We were interested in polymorphisms in this gene, since decorin expression in COPD patients is diminished.[9,10] Decorin plays a direct role in the repair processes after inflammation through its regulation of matrix metalloproteases and tissue inhibitors of metalloproteases.[27,28] Furthermore, decorin is the natural inhibitor of TGF-β1 and may therefore influence the repair process in the lung indirectly.