Considerations for selecting immunodeficient mouse strains for cancer xenograft models.

Preclinical (in vivo) experiments for efficacy and toxicity are predominantly conducted in mice. Nevertheless, human-derived cells, tissues, and organoids are generally rejected by the immune system of mice. Thus, immunodeficient mice are used as xenograft models to overcome immune rejection in cancer research. Xenograft mouse models are divided into ectopic, orthotopic, and metastatic models based on the transplant sites. Xenograft mouse models are established by transplanting cancer cells, tissues, or organoids derived from patients. These models show diverse success rates and production times depending on the transplant materials and recipient mice. In this review, mouse strains for the establishment of xenograft models in cancer research are introduced. Genetic engineering of immune cells, such as T cells, B cells, and natural killer cells, shows specific properties. To select an immunodeficient mouse strain, the differences in the characteristics of the models must be understood. Optimized mouse models can provide information to investigate cancer progression and evaluate anticancer drugs.