High levels of anti-oxidants, such as many vitamins, may aggravate late-stage cancer, a genetics pioneer says today.
Nobel laureate and double-helix discoverer Dr James Watson writes in the journal Open Biology on the role of antioxidants in incurable cancers, particularly those that have spread beyond the primary tumour.
Dr Watson, who is based in the USA, states: "Although mortality from many cancers has been steadily falling, particularly those of the blood, the more important statistic may be that so many epithelial cancers (carcinomas) and effectively all mesenchymal cancers (sarcomas) remain largely incurable."
He focuses on molecules called reactive oxygen species, or ROS, which are important in apoptosis – the beneficial death of old or damaged cells. ROS can also irreparably damage vital proteins and nucleic acid molecules such as DNA.
In healthy bodies, ROS are not needed and continuously neutralised by anti-oxidative proteins. Hence in late-stage cancer, Dr Watson believes, the consumption of foods rich in antioxidants could destroy much-needed ROS and actually promote cancer progression.
This paper is "among my most important work since the double helix," Dr Watson says.
Both chemotherapy and radiotherapy depend on the cell-killing ability of ROS, he says, which is "why cancers that become resistant to chemotherapeutic control become equally resistant to radiotherapy".
The reason why some cancer cells – including those driven by mutant proteins such as RAS and MYC – are the most resistant to treatment is due to their high levels of ROS-destroying antioxidants, he suggests.
This is because these proteins trigger more of a gene transcription factor called Nrf2, which controls the synthesis of antioxidants.
"This makes sense because we want antioxidants present when DNA functions to make more of itself," Dr Watson writes. "Unless we can find ways of reducing antioxidant levels, late-stage cancer ten years from now will be as incurable as it is today."
Watson, J. D. Open Biology January 9 2013
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