An intricate interplay between cancer cells and white blood cells outside a lung tumour can help to drive metastasis, the spread of the disease to other parts of the body.

Nathan Reticker-Flynn and Sangeeta Bhatia at the Massachusetts Institute of Technology in Cambridge focused on a molecule called galectin-3, which they found is expressed on the surface of certain white blood cells during early cancer in mice. Lung tumours secrete signalling molecules that mobilize these white cells — known to promote metastasis — out of the bone marrow and into the bloodstream.

Metastatic cells from the tumour display a cell-surface sugar that binds to galectin-3. As a result, these cells increasingly interact with the mobilized white blood cells in distant parts of the body, enhancing the cancer cells' ability to colonize and grow into new tumours.

Cancer Discov. http://doi.org/xdf (2014)