Resumen
Circulating tumor cells dissociate from the primary tumor, enter the bloodstream and travel to distant sites where they seed metastases. To endow these tumor cells with the features necessary for this journey, they must undergo dramatic shape changes, acquire migratory potential, alter their metabolism, and quickly adapt to insults in each new environment. To permit such phenotypic changes in multiple directions, they often acquire a more primitive state reminiscent of stem cells in the embryo. These changes are coupled with altered capacities and qualities to remove DNA lesions such as those induced by a metabolic shift or an immune cell attack. Defects in DNA repair cause mutations, leading to hereditary breast cancer and accelerating progression. Enhanced DNA repair causes resistance to chemotherapeutic treatment. Therefore, it is of utmost interest to understand the choreography of these functions in circulating tumor cells at the molecular level, because they represent targets to fight chemoresistant metastases.