Recently researchers at MIT and the University of California at San Diego tamed E. coli bacterium to release genetically engineered cytotoxic agents into tumor Cells. They use engineered bacteria cells as a drug delivery platform via co-culture with human cancer cells in vitro. The team made use of a common feature of bacteria to bloom in low-oxygen environments such as tumors and low defensive immune system. They deployed the engineered bacteria with a traditional cancer drug to the target site where the bacteria shrank aggressive liver tumors in mice. See the article