In this review, we will also describe the phenotypes of the first three genetically engineered hamster cancer models, Kos in the tumor suppressors TP53 and KCNQ1, and a KO in the IL2RG gene, whose first application was to provide a non-murine model to study X-linked severe combined immunodeficiency (XSCID) and the infectious diseases associated with IL2RG deficiency. The gene discussed is KCNQ1; the disease is cancer.