Our specific cancer research program is new to our laboratory in the
last two years. It is a growing part of our program. Currently, it is primarily
devoted the role of genetic polymorphisms in estrogen formation and disposition
in determining breast cancer risk. New aspects of the program that also
integrate with our molecular toxicology and comparative pharmacogenetics
program include studies on the role of P-glycoprotein and cyclooxygenase
2 expression in cancer.
Breast cancer has the highest incidence rate of all types of
cancers in women on Prince Edward Island and is second only to lung cancer
as a cause of mortality. It is estimated that breast cancer during 1998
will account for more than 30% of all cancer cases in women and approximately
19% of all cancer deaths. Approximately 10% of breast cancer cases are
familial, while the remaining 90% appear to be primarily related to other
factors. Even if cancer in an individual is not familial, the genetic make-up
of an individual can significantly influence the occurrence and growth
of a cancer.
Estrogen normally found within the body is known to be a risk factor
for breast cancer. Estrogen can directly promote the growth of some types
of breast cancer, but may also be involved in initiation breast cancer
through the formation of DNA damaging compounds. Because estrogen exposure
is a risk factor, it is predicted that genetic differences between women
in how their bodies handle estrogen would affect the risk of breast cancer.
A number of studies have suggested that genetic differences in enzymes
expected to influence estogen metabolism are associated with breast cancer
risk. However, further studies are required to confirm or clarify the findings
to date, not all relevant enzymes have been identified and studied, and
few studies have looked at women who carry multiple genetic variants. Understanding
which metabolic pathways influence the risk of breast cancer will help
to elucidate the role of estrogen in breast cancer risk, provide insight
into new methods for decreasing the risk of breast cancer, and possibly
provide a mechanism for assessing risk in women with no family history
of breast cancer.
As this is a new program for us, no peer-reviewed publications are currently available.