Expression of estrogen-related gene can impact post-menopausal breast cancer risk

In a study using a first-of-its kind mouse model of aging that mimics breast cancer development in estrogen receptor-positive post-menopausal women, investigators have determined that over-expression, or switching on of the Esr1 gene, could lead to elevated risk of developing estrogen receptor-positive breast cancer in older women.

In a second study from the same research lab, investigators found that in the specially bred mice given anti-hormonal drugs similar to those currently used by women to lower their breast cancer risk, the elevated risk of developing breast cancer due to over-expression of Esr1 could be lowered or reversed.

The findings appeared in the American Journal of Pathology.

The investigators followed the mice as they aged through their natural reproductive cycle and decreased circulating estrogen levels. They then looked to see what factors were involved in resulting cancers by comparing outcomes in mice that were designed to overexpress one of two different genes. They found that Esr1 over-expression resulted in more breast cancers and was accompanied by high activation of estrogen pathway genes.

Removing breast tissue, even with a fine needle, is still invasive and perhaps unavoidable. However, the authors have developed a method that requires collecting just a few tumor cells from a small tissue sample, as the process expands and grows the cells many-fold so that there can be adequate cancer cell numbers to run through prognostic tools.

Reference:

Study in mice suggests that expression of estrogen-related gene can impact post-menopausal breast cancer risk and prevention strategies; American Journal Of Pathology.