Researchers have worked out how certain cancer cells go into hiding in the body and emerge later to cause the disease to recur.

Cancer can reappear and spread through the body years after the primary tumour has been surgically removed. To find out more about this latent period, Joan Massagué at Memorial Sloan Kettering Cancer Center in New York and his colleagues isolated cells from human lung and breast cancers that formed tumours only months after being injected into mice. The team found that these cells entered a quiescent, slow-dividing state by inhibiting a signalling pathway driven by the protein WNT. The cells also expressed high levels of the stem-cell genes SOX2 and SOX9, which enabled the cells to grow into new tumours under certain conditions.

Moreover, the cells downregulated the expression of molecules that are recognized by immune cells called natural killer cells, allowing the latent cancer cells to hide from immune surveillance until conditions permitted them to form metastases.

Cell http://dx.doi.org/10.1016/j.cell.2016.02.025 (2016)