Vascular markers for murine tumours

Damage to the vasculature may represent an important component of several forms of cancer therapy. Methods for studying the structure and function of the vasculature of experimental mouse tumours are required. In this paper several relatively simple methods are described for the histological examination of the vascular structure of murine tumours. The methods have been applied to cryostat sections of two sarcomas and two carcinomas. Immunoperoxidase staining with polyclonal antibodies to laminin highlights the vascular basement membrane of sarcomas, but has limited use with carcinomas, while the monoclonal antibody MECA-20 is a good marker for the endothelial cells of all vessels in all four tumours tested. The presence of endothelial cells in normal tissues can also be demonstrated by the use of enzyme-histochemical techniques for alkaline phosphatase, 5'-nucleotidase and nucleotide diphosphatase (ADPase), but only one of these methods (ADPase) works consistently in tumours. The relative merits of these methods are discussed and in all cases related to the staining pattern obtained with normal mouse tissues. The significance of these methods for vascular targeting is also discussed.