There is a key phase in the progression of cancer. It occurs when cells that have left the primary tumor are placed in organs where they may in future cause metastases. What happens in this phase depends on the cancer being left behind as an illness already overcome or that reappears later.

Researcher Joan Massagué has now discovered how these cells capable of causing metastasis escape surveillance of the immune system and remain camouflaged for months or years. They do it by becoming a stem cell, reducing its activity to the minimum and eliminating from its membranes any signal that can draw the attention of immune cells. Like an animal that hibernates, they enter into a state of latency that makes them undetectable. More information