Human tumour xenografts.

The historical development, and more recent advances in the use of xenografts of human tumours as potential models for the study of human cancer are described and discussed. The practicality of the various systems available are critically reviewed, as well as their potential application in the field of experimental chemotherapy. Emphasis is given to the fact that over two decades of research effort has hardly produced any results of clinical relevance, often because workers have been too carried away with their technical achievements to appreciate the rules of experimental chemotherapy. The role of human tumour xenografts in the study of human cancer is appreciated, but the development of newer syngeneic, differentiated animal models may lessen their importance in the field of experimental chemotherapy.