Since endogenous FGF4 expression was most changed by PCR and ELISA in GDM patients, we also tested FGF4 expression at protein level by western blot and observed an increased expression of FGF4 in GDM patients, which is consistent with the results of RT-PCR and ELISA (Figure 1M) Interestingly, placental FGF4 levels were positively correlated (R2 = 0.65; p < 0.0001) with blood glucose level in both GDM and normal patients, and the correlation is even higher than FGF21 (R2 = 0.15; p < 0.01) (Figures 1J–L), suggesting that it may serve as a potential pathological marker of GDM. The gene discussed is FGF21; the disease is gestational diabetes.