HTRA1 and preeclampsia: Among 167 proteins tested, the expression of 5 proteins (EGFR, Flt-1, Calretinin, PAI-1 and HtrA) were positively correlated (Figure 3A) and four proteins (AnnexinXI, PDEF, PCNA and PlGF) were inversely correlated with the severity of preterm preeclampsia (P<0.05, R value≥0.4) (Figure 3B).