Human tumour xenografts: a critical appraisal.

Human tumours grown in immune-deficient mice are available for studies in experimental pathology and therapeutics. In addition to growth-delay experiments clonogenic assays can sometimes be performed. Xenografts often retain some characteristics of the source tumour but the amount of precise information on the maintenance of therapeutic sensitivity is small. Principal drawbacks include the difficulty of matching with human doses the dose of drugs given to the host mouse, and the probable existence of a substantial host reaction against the grafts. Principal benefits may be to studies that involve the intercomparison of human tumours in regard to therapeutic response.