After analyzing a half million gene mutations, the researchers found that although different gene mutations control different cancer pathways, each pathway was controlled by only one set of gene mutations.

This suggests that a molecular "survival of the fittest" scenario plays out in every living creature as gene mutations strive for ultimate survival through cancerous tumors. This finding, which appears in the August 2008 issue of The FASEB Journal, improves our understanding of how evolution shapes life in all forms, while laying a foundation for new cancer drugs and treatments.

"This study lays the groundwork for understanding the nature of different mutations in cancers," said Chen-Hsiang Yeung, first author of the study, "and helps with understanding the mechanisms of cancers and their responses to drug treatments."

To arrive at these conclusions, researchers analyzed about 500,000 cancer mutation records from the Catalog of Somatic Mutations in Cancer database and then divided the data into 45 tissue types. Within each tissue type, they calculated the frequency that multiple genes were mutated in the same sample. They identified the frequencies of mutations that were significantly higher or lower than if the genes had mutated independently. Then they mapped out how these genes ultimately lead to cancerous tumors and checked whether the genes occurring in specific tissues used the same or different cancer pathways.

"Little could Darwin have known that his 'Origin of the Species' would one day explain the 'Origin of the Tumor,'" said Gerald Weissmann, MD, Editor-in-Chief of The FASEB Journal. "This research report completely changes our understanding of the many gene mutations that cause cancer."

faseb/

"Women take them thinking they'll be a safe alternative to hormone-replacement therapy and they might help hot flashes," she said.

Those who have heard that hormone replacement can improve cardiac or brain function also hope that eating soy or taking genistein supplements will have the same effects, she said.

The effects of hormone replacement therapy (HRT) are more complex - and problematic - than once thought. A recent large-scale study of HRT in post-menopausal women was stopped because of an increased risk of stroke and blood clots in women taking estrogen alone, and a higher than average incidence of breast cancer, cardiovascular disease, blood clots and stroke in women taking estrogen and progesterone.

Studies of estrogen's effects on cognition have also had mixed results. In earlier studies, for example, psychology professor Donna Korol, a collaborator on the current project, found that estradiol enhances some abilities, such as place or spatial learning, while hindering others, such as learning that relies on stimulus-response associations, considered by some to be akin to "habit" and not fluid thought.

Performance in these tasks involves brain structures outside the prefrontal cortex.

The research indicates that multiple factors influence the effects of estradiol on the brain, Schantz said. The timing of the exposure, the types of brain functions or structures studied and the age of the test subjects can all generate different results, she said.

uiuc/