Smokers hear of cancer antidote

Aisling Irwing reports from the British Association for the Advancement of Science festival at Newcastle University.

Smokers could avoid getting cancer by taking a chemical that zaps the carcinogens they have breathed in before they start to cause cancer. And drugs working on a similar principle could protect people exposed to carcinogens through work or diet.

Researchers are developing a clutch of compounds called "therapeutic nucleophiles" that will either accelerate the body's natural defences against carcinogens or add to them.

Bernard Golding, from the chemistry department at Newcastle University, told the meeting of work to combat a carcinogen that is frequently and inadvertently eaten in China. Aflatoxin, which is produced by a mould that grows on certain badly stored foods and on peanuts, causes liver cancer. Once it is in the body aflatoxin turns into a potent form which heads for the DNA and attacks (alkylates) it. The body manages to neutralise some of it with glutathione, a naturally produced scavenger in the body.

But scientists from Johns Hopkins University in the United States have found that adding an enzyme, glutathione-S-transferase, catalyses the scavenging reaction, making it more effective. In rats fed aflatoxin, the chemical has prevented liver cancer. Trials have now begun in people.

Professor Golding also described his work in Newcastle: "We're trying to design a nucleophile that will enter cells passively and protect them against alkylating agents without the need for enzyme activation". Test-tube experiments have been successful and a potential candidate is the vitamin B12.

He said that the therapy could also treat workers who were accidentally exposed to a carcinogen or troops suddenly exposed to chemical warfare.

"A smoker could take additional tablets of glutathione," Professor Golding said.