SCGB3A2 is a secreted cytokine-like protein that binds to the scavenger receptor MARCO and various pathogens including L. monocytogenes, P. aeruginosa, and yeast 1. The protein strongly inhibits phospholipase A2 activity 2 and exhibits anti-inflammatory effects in respiratory epithelium while possessing anti-fibrotic activity in lung tissue 2. SCGB3A2 promotes branching morphogenesis during early lung development 2 and may inhibit FSH and LH production in the pituitary. Functionally, SCGB3A2 defines distinct secretory cell subsets in conducting airways 3 and is expressed in terminal airway-enriched secretory cells (TASCs) unique to distal airways 4. In disease contexts, SCGB3A2 expression is decreased in emphysema-specific alveolar type II cells in COPD 5 and is upregulated in aberrant intermediate epithelial cells during impaired lung repair in IPF 6. SCGB3A2 protects lungs from cigarette smoke-induced emphysema by upregulating α1-antitrypsin expression through STAT3-mediated signaling 7. SCGB3A2 promoter polymorphisms (rs6882292, rs1368408) are associated with asthma susceptibility 8 and the -112G>A polymorphism is associated with Graves' disease risk 9.