Animal models are extensively used to understand how cancer develops and spreads and to test the efficacy of novel therapeutic strategies. Preclinical cancer studies carried out on animal models fall into two broad categories, those using tumor cell transplantation and those in which tumors arise or are induced in the host. During the course of my PhD, I dealt with a wide array of different experimental studies based on xenografting of primary human tumor tissuesin immunodeficient mice. The aim of this thesis is to provide a basic panel for a pathological approach to human tumor xenografts in mice, with detailed references to subcutaneous (s.c.) xenograft models, intraperitoneal (i.p.) xenograft models and to promising metastatic models. The goal of my three-year-research is to critically evaluate how each model has been utilized to provide insights into human cancer therapy and to provide an assessment of the strengths and limitations of each model
