Blood test
Blood samples were taken from just over 1,900 women © PublicDomainPictures

Hormone could indicate breast cancer risk

A new study from Sweden’s Lund University shows that women with low levels of an anti-stress hormone have an increased risk of getting breast cancer.

The investigation, part-funded by the European Research Council, is the first of its kind on humans and confirms previous similar observations from experiments on animals. The investigation focused on enkephalin, a hormone that circulates freely in the blood with pain and anxiety-reducing properties. Enkephalin also reinforces the immune system by directly affecting immune cells.

Commenting, Professors Olle Melander and Mattias Belting, said: “Among women with the lowest levels of the hormone, the risk of breast cancer was more than three times that of the women with the highest levels of the hormone. This is one of the strongest correlations between cancer risk and a freely circulating biomarker ever described”.

The study was based on blood samples taken from just over 1,900 women in Malmö, which were followed up with regards to breast cancer for an average period of 15 years. The results confirm a statistical correlation between low enkephalin concentrations in the blood and increased risk of breast cancer. However, it remains unknown whether there is a causal relation showing that a low level of the hormone directly affects tumour development.

The researchers at Lund University hope that after further studies, the results will facilitate prevention and early detection of breast cancer. For those with an increased risk of breast cancer, potential preventive treatments could take the form of lifestyle interventions to reduce stress and new drugs. The findings also play into the development towards individualised risk assessment and treatment based on each woman’s needs.

The results are presented in the Journal of Clinical Oncology.