TFF2 and idiopathic pulmonary fibrosis: Single nucleotide polymorphisms (SNPs) of the SP genes have been shown to associate with various acute and chronic pulmonary diseases, such as idiopathic pulmonary fibrosis (IPF) (13), chronic obstructive pulmonary disease (COPD) (14, 15), acute respiratory distress syndrome (10), cystic fibrosis (16), and neonatal respiratory distress syndrome (RDS) (17–20).