Breast Cancer Risk Driven By Estrogen-Raising Gene

A recent study says that scientists have discovered the first direct connection between levels of estrogen in younger women and the risk of breast cancer. Researchers discovered that a change in a gene can affect how of estrogen is broken down, and it is related to a decrease in the risk of breast cancer risk in pre-menopausal women. Sex hormones such as estrogen play an important role in breast cancer development. Dr Olivia Fletcher from the ICR's Breakthrough Breast Cancer Research Centre said, "This is the first time anyone has found a DNA change that is directly associated both with hormone levels and breast cancer risk in younger women. Scientists have suspected this link exists, but no one has been able to prove it until now.”

Researchers at the Breakthrough Breast Cancer Research Centre at The Institute of Cancer Research (ICR) and the London School of Hygeien and Tropical Medicine (LSHTM), and their team in the UK and Ireland sought to determine which genes are involved in the synthesis or breakdown of sex hormones. The team measured the hormone levels in over 700 healthy pre-menopausal women's urine and blood in a process designed to take into consideration hormone level variations during menstrual cycles because it is known to impact the synthesis or breakdown of sex hormones.

This study found one genetic variant, estrone glucuronide, appeared more frequently in women with lower urinary levels of a particular breakdown product. The variant was linked to a 22% reduction in estrone glucuronide levels and consisted of one single letter change in the DNA at position 7q22.1, which is close to the CYP3A gene. The researchers found this particular variant in another study with 10,551 breast cancer patients and 17,535 healthy controls. They found that the change in DNA change seemed to be more frequent healthy controls. They found a 9% reduction in breast cancer risk in women diagnosed at the age of 50 or younger, but no reduction was observed in women above the age of 50 years.

CYP3A4 belongs to the family of CYP3A genes, which is responsible for breaking down approximately 50% of all clinically used drugs, including some used in breast cancer therapy. This means that their findings may have other uses, and the research may be an important step in further understanding of the link between hormones and breast cancer. These findings have an effect on the monitoring and treatment of breast cancer in the future.