Xenograft Model C19812 Xenograft_Model Xenograft Model C1520166 An experimental system in which (usually) human tumor cells are transplanted into immunocompromised mice that do not reject human cells; cells may be implanted under the skin or into the organ type in which the tumor originated. These model systems may be used for drug development and studies of molecular biological mechanisms of cancer. Experimental Model of Disease Xenograft Model Pharmacology: Pharmacodynamic Drug Interactions