PAPPA2 and preeclampsia: Among the proteins with significant fold changes in EOPE compared to healthy controls, a series of proteins have previously been reported as biomarkers of preeclampsia, including serpin family A member 5 (SERPINA5)23, pappalysin 2 (PAPPA2)24,25, hepatocyte growth factor activator (HGFAC)26,27 and thymosin beta-4 (TMSB4X)28.