Cancer metastasis to the bone: Mechanisms and animal models (Review)

The majority of cancer-related deaths result from tumor metastasis, with bone metastasis occurring in almost all types of malignant tumors. Understanding the mechanism by which tumors metastasize to bone is critical for the identification of novel therapeutic targets. A large amount of research has been carried out using animal models, and these models have been crucial in advancing the fundamental understanding of cancer. However, current models are limited; although they can mimic specific stages of the metastatic process, they are not able to replicate the entire process from tumorigenesis to bone metastasis. The present review describes the molecular changes that occur in the intraosseous microenvironment of bone metastases, including osteolytic and osteoblastic types, and summarizes advancements in animal models of bone metastasis.