Autophagy, senescence and tumor dormancy in cancer therapy.

The relationships between autophagy and apoptosis have been examined quite extensively and have often been shown to be reciprocally regulated responses to stresses such as exposure of tumor cells to chemotherapeutic drugs and radiation. However, there is now evidence that autophagy may also play a role in tumor dormancy. Given that tumor dormancy and disease recurrence are poorly understood phenomena which are nevertheless critical elements of patient morbidity and mortality, this commentary develops the postulate that autophagy and senescence may be coupled responses that influence the capacity of the tumor cell to maintain a prolonged state of growth arrest that can be succeeded by tumor regrowth and disease recurrence.