A new study from Karolinska Institutet in Sweden shows that a certain type of white blood cell in breast tumours can both prevent and promote the spread of cancer cells to other organs. This may have implications for the prognosis and treatment of breast cancer. The study is published in the scientific journal Cell Reports.

Breast cancer is a common cancer that can spread to other parts of the body such as the lungs, brain and bone marrow. White blood cells called tumour-associated macrophages (TAMs) are abundant in breast tumours and are thought to influence the spread of cancer, for example by stimulating the formation of new blood vessels.

Researchers have now studied a type of TAM that produces the substance VEGF-C. This substance promotes the formation of lymphatic vessels, which can facilitate the transport of cancer cells to other organs. However, these TAMs were found to have a paradoxical effect; they reduce the spread of breast cancer to the lungs but at the same time increase the spread to the lymph nodes. In samples from patients with breast cancer, the researchers found that the presence of VEGF-C-positive TAMs was associated with milder disease.

“So it seems that these white blood cells play a protective role,” says Charlotte Rolny, associate professor at the Department of Oncology-Pathology, Karolinska Institutet who led the study. “Ultimately, these findings may lead to new treatment strategies that redirect cancer cells to the lymph nodes where they do less harm.”

The research was mainly funded by the Swedish Research Council, the Swedish Cancer Society, and Radiumhemmet’s research funds.

Source: Karolinska Institutet