Increased concentrations of the pregnancy hormones estradiol and progesterone were associated with an increased risk for hormone receptor-negative breast cancer diagnosed before age 50, according to the results of a nested case-control study presented at the 11th Annual American Association for Cancer Research International Conference on Frontiers in Cancer Prevention Research.
The research was small—only 640 women, most of them with hormone-positive breast cancer—but the study might encourage continued research on the link between pregnancy and TNBC. Samples were taken in the first trimester. Interestingly, the association was stronger for PR-negative tumors than for ER-negative. And stronger for women under 50 than for those over 50.
“Pregnancy influences maternal risk for breast cancer, but the association is complex and the biological mechanisms underlying the associations are unknown,” said Annekatrin Lukanova, M.D., Ph.D., associate professor at the German Cancer Research Center in Heidelberg, Germany. “Understanding the mechanisms underlying the protective effect of childbearing on cancer risk can form the basis for primary prevention of breast cancer.”
Check out the abstract and more information here.