The V2 carcinoma of the rabbit as an integrated model of tumor invasion.

The V2 carcinoma, established from skin carcinomas of cottontail rabbits and transplantable in all strains of domestic rabbits, is a paradigm of invasiveness attainable by squamous cell carcinoma. The main mechanisms contributing to this potential are the pressure of incessant cell proliferation, the capacity of the tumor to grow in compact as well as in dissociated formation, the synthesis of proteinases (chiefly cathepsin B and collagenases) by the tumor cells, and the latter's migratory activity. In addition, the V2 carcinoma elicits a large spectrum of host reactions which favor partly the organism, partly the tumor and thus create the complexity of the invasion phenomenon.