Tumor vessel stabilization by increased VEC has been shown to reduce tumor metastasis.44,45 Ezh2 expression is increased in tumor-associated ECs, and this has been linked to increased vascular density and reduced vessel maturation.31 Our results show that reduced VEC and increased EZH2 nuclear staining in human ovarian carcinoma vessels parallel the downregulation of Claudin-5 and VE-PTP, suggesting a possible alteration of the identified signaling mechanism. Here, CLDN5 is linked to ovarian carcinoma.