Bacterial vectors, as microscopic living 'robotic factories', can be reprogrammed into microscopic living 'robotic factories', using a top-down bioengineering approach to produce and deliver anticancer agents. Most of the current research has focused on bacterial species such as Salmonella typhimurium or Clostridium novyi. However, Escherichia coli Nissle 1917 (EcN) is another promising candidate with probiotic properties. EcN offers increased applicability for cancer treatment with the development of new molecular biology and complete genome sequencing techniques. In this review, we discuss the genetics and physical properties of EcN. We also summarize and analyse recent studies regarding tumour therapy mediated by EcN. Many challenges remain in the development of more promising strategies for combatting cancer with EcN.