DLL4 and ovarian neoplasm: The authors reported that the expression of VEGF, VEGFR1, Dll4, Notch1, or Notch3 in ovarian tumor tissues was higher than that in normal or benign ovary tissues (p < 0.05) while in the tumor tissues, Dll4 was positively correlated with VEGFR1 expression and Notch1 was positively associated with VEGFR2 and MVD.