The treatment of mice with intratracheal BLM instillation resulted in an increase in syndecan-4 in the lungs, and the results from the in vivo experiments using Sdc4KO mice showed that the lack of this HSPG resulted in a significant increase in pulmonary fibrosis with more Smad3 activation following treatment with BLM. The gene discussed is SMAD3; the disease is pulmonary fibrosis.