 So metastasis is very interesting because how do you mutate a cell? Think about a breast cell or a lung cell. A lung cell, the way we typically think about metastasis is that it grows, it grows, it grows, breaks off, and then lodges into your lung. How does it survive or lodges into your bone? How does a lung cell survive in the bone? Like the matrix is completely different. There's nothing there. A breast cell is like, hey, where's all the milk docs? There's nothing in this liver. It's going to get killed. Why would it evolve how to survive in a lung cell? Why would it evolve the ability to survive in the liver? It makes no sense at all that that's what it should do. It can only do that if it evolves that ability.