This also confirms our previous observation that Akt1-mediated endothelial-barrier modulation is predominantly through expression modulation of claudin-5 and not ZO-1/2.14 Most importantly, in a VECad-Cre-Akt1 mouse model, murine RM1 metastatic prostate cancer cells showed a significant increase in the rate of metastasis to the lungs, but not on the growth of tumour xenografts. This evidence concerns the gene CLDN5 and prostate cancer.