Chapter 16 – Brain Metastasis of Colorectal Cancer: Microenvironment and Molecular Mechanism

Colorectal cancer is one of the most common digestive tract malignancies in the world. Owing to the brand new systemic therapies, the patients’ life expectancy is remarkably prolonged, and the incidence of brain metastases is increasing. However, the underlying mechanism of brain metastasis is currently meager. As the “seed and soil” theory described, specific tumor cell clones have the potential to invade and migrate. Numerous molecules such as epidermal growth factor receptor are involved in this process. On the other hand, the structure of the blood–brain barrier creates a unique condition for brain, and the microenvironment of the central nervous system may alter the destination of the disseminated metastatic cells. Evidences also showed that certain factors such as chemokines and microRNAs are also involved in the site-specific metastasis. Last but not least, the available preclinical models of brain metastasis and their use as tools to advance knowledge of the biology of the disease may help to understand the mechanisms that regulate the brain metastatic phenotype.