How Does Pregnancy in young age Reduce Breast Cancer Risk?

How Does Pregnancy in young age Reduce Breast Cancer Risk?

Latest research published in journal: Breast Cancer Research
(28th April 2013)

Being pregnant while young is known to protect a women against breast cancer. But why? Research in BioMed Central's open access journal Breast Cancer Research finds that Wnt/Notch signalling ratio is decreased in the breast tissue of mice which have given birth, compared to virgin mice of the same age.

Early pregnancy is protective against breast cancer in humans and in rodents. In humans having a child before the age of 20 decreases risk of breast cancer by half. Using microarray analysis researchers from Basel discovered that genes involved in the immune system and differentiation were up-regulated after pregnancy while the activity of genes coding for growth factors was reduced.

The activity of one particular gene Wnt4 was also down-regulated after pregnancy. The protein from this gene (Wnt4) is a feminising protein -- absence of this protein propels a fetus towards developing as a boy. Wnt and Notch are opposing components of a system which controls cellular fate within an organism and when the team looked at Notch they found that genes regulated by notch were up-regulated, Notch-stimulating proteins up-regulated and Notch-inhibiting proteins down-regulated.

Reference of Journal : Parity induces differentiation and reduces Wnt/Notch signaling ratio and proliferation potential of basal stem/progenitor cells isolated from mouse mammary epithelium. Breast Cancer Research, 2013.