Increased expression of H/T-cadherin in tumor-penetrating blood vessels

Neovascularization is a prerequisite for tumor growth. Thus, selective dest ruction of the tumor vasculature should prevent tumor expansion. We have es tablished a method to identify proteins that are specifically expressed on the surface of endothelial cells in tumors. CD31-positive endothelial cells were isolated from Lewis lung carcinoma Lung metastases as well as from no rmal lung tissue. cDNAs derived from these cells were subjected to a subtra ctive hybridization procedure, and cDNAs overrepresented in tumor-derived e ndothelial cells were isolated; those encoding surface proteins were select ed using a signal sequence trap assay. One isolated cDNA encoded H/T-cadher in. In this report, we show that mouse H/T-cadherin is overexpressed on end othelial cells of several tumors, whereas it is expressed only on a subset of endothelial cells in healthy organs. On the basis of the expression of H /T-cadherin in lung metastases of different tumors, we suggest that differe nt tumors can have a differential influence on the expression of endothelia l cell surface proteins.