Analysis of the expression levels of EGFR family members revealed that HCMECs express significantly higher levels of EGFR-1, HER2 and HER4 than dermal or brain microvascular endothelial cells; however, the HER2 did not appear to be functional as neuregulin did not evoke HER2 phosphorylation and a subsequent intracellular signalling response (Fig. 5A) and proliferation (Fig. 5B) in the HCMECs in contrast to the A2780 ovarian cancer cells (Fig. 5A-C). This evidence concerns the gene ERBB4 and ovarian cancer.