Researchers Find Link Between Early Pregnancy and Reduction in Breast Cancer Risk

A latest research provides an explanation for how an early pregnancy reduces the risk of breast cancer by half.

The research was conducted on rodents.

Published in BioMed Central's open access journal, Breast Cancer Research, the study found that Wnt/Notch signaling ratio was decreased in the breast tissue of mice, which gave birth, compared to virgin mice of the same age. Wnt and Notch are two different components of a system which controls cellular fate within an organism.

According to the study, the chances of getting breast cancer are reduced by half in humans if they have a child before the age of 20. Researchers from Basel found that after a pregnancy the immune system and differentiation genes get a boost and the genes for coding of growth factors get reduced. They used microarray analysis technique for the study.

The activity of one particular Wnt4 gene gets down-regulated after pregnancy. The protein from this gene is a feminizing protein. In simpler words, absence of this particular protein forces a fetus to develop as a male.

The researchers found that genes regulated by Notch, which is an opposing component of Wnt, were up-regulated.  Notch-stimulating proteins up-regulated and Notch-inhibiting proteins down-regulated.

The pregnancy permanently altered the Wnt/Notch signaling ratio in the progenitor cells of mammary tissue of mice. Mohamed Bentires-Alj from the Friedrich Miescher Institute for Biomedical Research, who led this study explained, "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."