Having a baby before the age of 20 could cut the risk of breast cancer in half, a new study finds.
Researchers followed the activities of certain genes in the breast tissue of mice who just gave birth compared to their virgin peers who had not, Medical Daily reported.
They found that the Wnt/Notch signaling ratio, which are pathways that control a cell's fate during development, was significantly reduced in mice that gave birth. This means the pathways are altered in women 20 years or younger who give birth thereby reducing their risk of getting breast cancer by half.
The genes involved in the immune system functions and differentiation were highly active after birth, while the genes that coded growth factors declined in activity.
"The down-regulation of Wnt is the opposite of that seen in many cancers, and this tightened control of Wnt/Notch after pregnancy may be preventing the runaway growth present in cancer," said lead author Mohamed Bentires-Alj of the Friedrich Miescher Institute for Biomedical Research, in a press release.
Previously, the reasons behind why early pregnancy was warding off breast cancer were mysterious and unresolved, but this latest study using a microarray analysis approach explains why a young pregnant woman's immune system gets a boost and a cancerous fate was prevented.
"This finding was specific for basal stem/progenitor cells and was associated with downregulation of potentially carcinogenic pathways," the authors wrote.
Wnt4 protein is also known as a feminising protein. Without this protein, it increases a woman's chance of having a baby boy.
The study appears in BioMed Central's open access journal Breast Cancer Research.