Fetal Environment May Influence Adult Cancer Risk
In mice, boosting uterine antioxidant levels also raised offspring's lifetime odds for cancer
WEDNESDAY, March 29, 2006 (HealthDay News) -- Molecular changes in the fetal environment, including altered levels of antioxidants, may affect cancer risk later in life in mammals, Canadian researchers report.
"We know that cancer-causing agents can travel across the placenta and harm the developing embryo or fetus," lead researcher Peter Wells, of the Leslie Dan Faculty of Pharmacy at the University of Toronto, said in a prepared statement. "This study provides the first direct evidence that changing the uterus's molecular environment -- in this case, by increasing the presence of antioxidants by adding vitamin E to the mice's diet -- alters the carcinogenic process in adult life."
The researchers studied pregnant mice genetically altered to lack one or both copies of the p53 gene, which causes a high rate of cancers in their offspring. Before and during pregnancy, the mice were given either a normal diet or a diet with a high dose of vitamin E.
The study also included two control groups of pregnant mice with both copies of the p53 gene intact. One control group received a normal diet and the other control group received a diet supplemented with a high dose of vitamin E.
The offspring off all the groups were observed for DNA damage and signs of cancer.
"Increased levels of vitamin E reduced in utero deaths among the offspring from 40 percent in the control groups to 5 percent in the test groups. In contrast, surprisingly, it also increased the onset of cancer in the offspring," Wells said. "Offspring that were exposed to vitamin E and lack one or both copies of the (p53) gene developed cancers 9 percent to 21 percent faster than the equivalent control groups."
Preliminary studies using a much lower dietary dose of vitamin E found a protective effect against cancer. This suggests that making certain adjustments to the molecular environment in the uterus may provide a fetus with increased protection from oxidative stress and delay or slow the onset of some cancers later in life.
The study appears in the current issue of Carcinogenesis.
The U.S. National Cancer Institute has more about cancer.