Health Canada seeks input on adding anti-cancer drug to junk food.

<Okay now guys . . . what do you NOT run to the health food store to feed the chemo kids? That's right, asparagine!>

Asparaginase does not occur naturally in humans, but it is found in bacteria, plants, and many animals, including guinea pigs. Asparaginase for chemotherapy is usually isolated from cultures of E. Coli bacteria. Another form is isolated from Erwinia; the Erwinia form has both advantages (can cause less of an allergic reaction) and disadvantages (might not be as active, is sometimes difficult to obtain from the manufacturer). Another common form is PEG-asparaginase; this is the E-coli enzyme stabilized with polyethylene glycol (PEG). PEG asparaginase might be more effective than the plain asparaginase. PEG asparaginase has a longer "half life" in the body and thus does not have to be given on the Mon-Wed-Fri schedule used for E. Coli asparaginase (fewer doses are necessary). PEG asparaginase also causes fewer allergic reactions. All three forms of asparaginase were used and compared in ALL trials in the 1990s and early 2000s.

Asparaginase was "discovered" about 35 years ago. They found that guinea pig serum (Kidd) suppressed the growth of lymphosarcomas in mice; asparaginase was later shown to be the active factor. It's not like the scientists knew that tumor cells has a low level of asparagine synthetase and designed the asparaginase treatment, rather, they found the treatment and worked backwards to find out why it worked.