Analysis of mouse model pathology: a primer for studying the anatomic pathology of genetically engineered mice

This primer of pathology is intended to introduce investigators to the structure (morphology) of cancer with an emphasis on genetically engineered mouse (GEM) models (GEMMs). We emphasize the necessity of using the entire biological context for the interpretation of anatomic pathology. Because the primary investigator is responsible for almost all of the information and procedures leading up to microscopic examination, they should also be responsible for documentation of experiments so that the microscopic interpretation can be rendered in context of the biology. The steps involved in this process are outlined, discussed, and illustrated. Because GEMMs are unique experimental subjects, some of the more common pitfalls are discussed. Many of these errors can be avoided with attention to detail and continuous quality assurance.