Lifestyle and environmental factors and cancer

[Guest guest]

The link below is about the two mutant genes making some women more prone to

breast and ovarian cancer but what I found of special interest was this:

The study shows, for example, that moderate exercise and

maintaining normal weight can significantly delay the onset of breast

cancer, even in women who inherit the most dangerous mutations.

The report also finds an enormous increase in the risk of breast

cancer in American women with the mutations who were born after

1940, compared with those born with the same mutations before

1940. That suggests that changes in American women's environment

or lifestyle have vastly added to the risk conferred by these genes......

........ genes are not destiny, the study also showed. Women whose lifestyles

in their teens and twenties included moderate exercise -- such as lots of

walking or some recreational dancing-- pushed back by many years the onset

of the disease. Avoiding obesity also helped substantially. It is not clear

what the protective mechanisms are, but these and other factors

that the study found helpful -- including pregnancy earlier in life and late

onset of first menstruation -- all reduce lifetime ovarian production of the

hormone estrogen, which can feed breast tumors.

" There's been a general feeling that those effects would be small and the

mutation would be the big effect on risk, but this shows there is a big

influence by environmental factors, " said Sharon Plon, director of the

Baylor Cancer Genetics Clinics in Houston.

http://www.washingtonpost.com/wp-dyn/articles/A9561-2003Oct23.html