Can soy components prevent prostate enlargement and mammary cancer in high risk individuals?

Progress Year 1:

	
During the first year of support, we have increased the size of our
breeding colony of MT-hGH transgenic mice and started assigning
available animals to the control, low- and hi-soy phytoestrogens diet.
As of today, 38 MT-hGH transgenic and 54 normal mice have been assigned
to different diets for a total of 92 animals in the study.

The animals are monitored daily and weighed monthly.  As of today, no
grossly visible mammary tumors in females or indices of
urinary/reproductive tract abnormalities in males have been detected.
This is consistent with the age of animals currently enrolled in this
study and the age-related incidence of these lesions.

We are also monitoring cancer incidence in a C-FAR supported study of
the effects of dietary soy components on longevity.  This study was set
up earlier using 409 animals and currently involves 326 mice.  As of May
15, 2000, 13 females from this study had to be sacrificed because of
mammary tumors.  The small number of animals that reached this stage of
tumor development is too small to allow statistically valid
conclusions.  However, numerical differences between groups suggest a
tendency for animals fed diet high in soy components to develop tumors
at a slightly more advanced age.  We are experiencing some difficulties
due to development of skin lesions that necessitate eliminating animals
from the study.  The incidence of these lesions does not differ in
groups fed different diets and preliminary studies of serum and liver
lipids argue against nutritional imbalance being involved.

Both studies are ongoing, animals that are sacrificed are preserved for
future histopathological analysis and arrangements have been made for
performance of this analysis by a highly trained mouse pathologist at
the Gerontology Center at the University of Texas Health Science Center
in San Antonio.