Even after tobacco companies had pledged to become more responsible about the public health effect of cigarettes, industry executives were attempting to undermine a landmark 1996 study showing a direct genetic link between smoking and lung cancer, a new report has said.

The report by researchers from the University of California, San Francisco, found that tobacco companies funded research designed to cast doubt on the study and then used their ties with the editor of a scientific journal to have the articles published, without disclosing the authors’ or editor’s connections to the tobacco industry.

Both studies were published in Mutagenesis, owned by Oxford University Press. Its then editor-in-chief, James Parry, received tobacco industry funding from 1986 until at least 2001, including £ 600 in 1993 for consulting work from British American Tobacco, the UCSF report alleged. Activist Stanton Glantz, a UCSF professor of medicine, is the lead author of the report being published today in The Lancet, a British medical journal.

Scientists at the Beckman Research Institute in Duarte, California, found in lab experiments that a component of tobacco smoke caused mutations in a gene known as p53, a so-called tumor suppressor that helps prevent cancerous growths. When the p53 gene is damaged, it can lead to uncontrolled cell growth.

The 1996 study was the first to prove the actual molecular mechanism by which cigarette smoke caused cells to grow into tumors. Nonetheless, the industry tried to downplay the significance of the 1996 study on smoking and p53, the UCSF report has found, and also launched studies designed to contradict its findings. The UCSF report focuses on two studies whose results were published but authors’ links to industry not mentioned.