An Escherichia coli toxin responsible for food-poisoning outbreaks associated with contaminated hamburgers might have a more palatable role as an anticancer agent. In a paper in Oncology Research (11, 33–39, 1999) , scientists at the Hospital for Sick Children (Toronto, Ontario) and the University of Toronto report using the verotoxin 1 protein to treat human astrocytomas xenografted into nude mice. Tumors injected with the toxin regressed completely and did not return, and the treated mice suffered no obvious side effects. Senior author Clifford Lingwood says that no other treatment has shown similar efficacy in the mouse system. In "hamburger disease", verotoxin targets a receptor, found in the developing blood vessels, that is absent from the glomeruli of adult kidneys, but is expressed in newly developing blood vessels of astrocytomas, as well as some multidrug-resistant tumors. In the mouse system, verotoxin caused the grafted astrocytomas and their associated blood vessels to undergo apoptosis. "As tumor cells become resistant to standard chemotherapy, they become more sensitive to this approach," Lingwood adds. Ottawa-based company Select Therapeutics plans to develop verotoxin for clinical use, and phase I trials are currently being designed.