The strategies used by the tobacco industry to counteract research linking tobacco smoke to cancer-causing mutations in a gene called p53 are detailed in a study published in The Lancet.
Damage to the p53 gene leads to uncontrolled cell division. Mutations in this gene are found in over 50% of all human tumours, including 60% of lung cancers.
Benzo[a]pyrene, a potent carcinogen, was identified in cigarette smoke in 1952. In the 1990’s, studies demonstrated patterned changes in p53 after exposure to benzo[a]pyrene. A 1996 landmark study showed benzo[a]pyrene’s interaction with p53 mirrored mutations found in actual human lung tumours. This finding provided strong molecular evidence of the direct carcinogenic effect of a tobacco smoke constituent.
Stanton Glantz (University of California, San Francisco, USA) and colleagues examined 43 previously confidential tobacco industry documents relating to p53 and tobacco smoke. The researchers found that prior to 1996, several tobacco companies supported research projects investigating the mechanisms of p53 mutations. Following the 1996 landmark study, tobacco companies planned a number of research projects in response and supported studies which appeared to cast doubt on a link between p53 damage and benzo[a]pyrene in tobacco smoke.
In two instances research arguing against a connection was undertaken and published by individuals with links to tobacco companies. Both studies were published in a journal, whose editor-in-chief, has an extensive and undisclosed history of working as a tobacco industry researcher and consultant.