Characterizing Rat Cancer Models
Decades of research on rats as a model system have provided a wealth of data on their genomics and phenotypes. The infrastructure to support rat research from a genomic perspective continues to be developed to enable most of the same types of germline and other modifications that have been common for mouse models. The models developed with genetic alterations can be used in many of the same ways as mouse models.
An extensive history of rats as a model for physiological and toxicology studies has provided many tools and reference data sets that offer information about rat phenotypes that can serve as a basis for comparisons among strains, treated animals, and with other organisms including humans.
Sequencing of the rat genome has provided a foundation for assessing the genotypes of rat strains. The Brown Norway (BN) strain was used to provide the reference sequence to which other rats can be compared. This does not mean to indicate the sequence is “normal” or not affected by disease, but merely serves as the sequence upon which the community has agreed forms the reference point, and has the specific genome coordinate map that helps the community to understand where the nucleotide or structural variation of other animals is located. As with other species, the single nucleotide polymorphisms (SNP) and copy-number variations (CNV) may play also an important role in understanding the biological impact of genome variations among strains. These may also yield important clues for comparison to tumors, as both primary and metastatic tumors may carry informative SNPs and CNVs as well. For more details about the strategies used for genotyping cancer models, explore the Genotyping section.
Rat phenotyping has provided a huge range of standard measurements that evaluate the biological characteristics over decades of research using rat models. Data from many strains has been collected, and excellent sources of this data include the Rat Genome Database (RGD) Phenotypes and Models Portal, and the National BioResource project in Japan. This data has been obtained for strains across various ages, disease conditions, and treatment situations. Data from newly developed models can be compared to existing data sets to obtain valuable insights. For more details about the strategies used for phenotyping rat cancer models specifically, explore the Phenotyping section.