Reprogrammed Macrophages Promote Spread of Breast Cancer; Macrophages Are Altered by Interaction with Tenascin, an Extracellular Matrix Protein Produced by Breast Cancer Cells

Early lung metastasis in a mouse: arrows indicate metastatic breast cancer cells (brown) colonizing the lung (blue). Cell nuclei are stained dark blue. (Source: Oskarsson /HI-STEM and DKFZ).

Metastatic breast cancer cells alter macrophages, a type of immune cell, to promote the settlement of cancer metastases in the lungs. The reprogrammed macrophages stimulate blood vessel cells to secrete a cocktail of metastasis-promoting proteins that are part of the so-called metastatic niche. This was demonstrated by scientists from the German Cancer Research Center and the Stem Cell Institute HI-STEM* in mice that had been transplanted with human breast cancer cells. The work enabled the scientists to identify new targets and develop initial concepts to better restrain the metastatic spread of breast cancer.