SCGB3A2 and pulmonary fibrosis: Based on previous studies of exogenous administration of SCGB3A2 to normal C57BL/6 mice [17,18] and the current study using Scgb3a2-null mice in the BLM-induced pulmonary fibrosis model, the levels of SCGB3A2 in the lung appears to be critical in suppressing pulmonary fibrosis regardless of whether it is given exogenously or being endogenously present in vivo.