For many years, scientists have known that women who get pregnant when they are young are far less likely to get breast cancer than women who have their first pregnancy after age 30.
A team of researchers from Texas A&M University, Duke University and the University of North Carolina may have discovered one possible reason for this discrepancy. They have determined that Alpha-fetoprotein, a protein produced by the fetus during pregnancy, can have a protective effect by interfering with breast cancer cells' ability to grow and reproduce.
Alpha-fetoprotein, a fetal growth-regulating protein, also has been found under certain conditions to inhibit the growth of breast cancer cells, according to Barbara Richardson, a researcher in the School of Rural Public Health at Texas A&M.
"At some point in the future, it's possible that this protein could be used to prevent breast cancer by being administered to women before they have clinically identifiable breast cancer," Richardson believes. She and colleagues Barbara Hulka, Clause Hughes, James Calvin and Jennifer Peck describe their research in the current issue of American Journal of Epidemiology.
Their findings show that women whose first pregnancy is at age 30 or older do not seem to have the same type of Alpha-fetoprotein, and "they experience growth promotion rather than growth suppression of any breast cancer cells present during pregnancy," says Richardson.
Researchers have speculated that the older a woman was before her breasts became mature from pregnancy, the more time the breast cells had to develop genetic defects that could lead to breast cancer. But early pregnancy appears to short-circuit this effect and offers long-term protection from breast cancer. "The women in our study with high Alpha-fetoprotein levels during pregnancy before the age of 30 show exactly this reduction in risk of developing breast cancer," Richardson confirms.
Richardson and her colleagues analyzed blood serum from pregnant women who were patients in California's Kaiser Permanente clinics during the 1950s and 1960s. They studied almost 600 women - 225 who had developed breast cancers, and 348 "controls" who had remained healthy over the 30-year follow-up period.
Richardson said their findings support the theory that the women who did not develop breast cancer had high levels of Alpha-fetoprotein in their blood during pregnancy. "The protective effect of high levels of Alpha-fetoprotein depended on how early in a woman's life she became pregnant," Richardson adds. "Younger women with high levels of Alpha-fetoprotein had the highest amount of protection. In our study, we estimated that a woman whose pregnancy was before the age of 20 had about one-half the risk of breast cancer as a woman whose first pregnancy was not until age 26 or beyond," Richardson said.
The research team hopes its findings will lead to the eventual use of Alpha-fetoprotein in breast cancer prevention. "We still need to learn many things, but suppose we know for sure that some segment of the Alpha-fetoprotein could be given to young women during pregnancy and perhaps prevent them from developing breast cancer?" Richardson asks. "If we knew this, it would be terribly exciting."
For more information, call Richardson at (409) 862-6672.
or Tura king, [email protected]
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