Researchers at Einstein have found that potent immune system cells that usually defend against cancer can actually promote it.
The research team from Albert Einstein College of Medicine of Yeshiva University analysed the movement of breast cancer cells in mice to show that a distinct population of macrophages, the immune system cells, can promote cancer metastasis.
Einstein cancer research specialist Dr Jeffrey W. Pollard, and seven colleagues believe that the new discovery offers a potentially useful new target for anti-cancer therapy.
In three different ways, the scientists showed that metastatic tumour growth is inhibited if these unusual macrophages are killed.
They also showed that even after breast cancer cells have lodged in the animals' lungs and started aggressive growth, erasing the special macrophages dramatically slowed growth of the metastasized tumours.
"This suggests that anti-macrophage therapy will have an impact in patients even with metastatic disease," said Pollard.
Based on this new work, he added, "macrophages themselves, or their unique signalling pathways, represent new therapeutic targets that may be efficacious in reducing cancer mortality."
The new study is published online in PLoS ONE.