Metastasis is like a tumor cell getting on a plane – alot has to happen for it to succeed at its final destination. Oncogenesis – the process by which cancer cells are derived, is initially slow at first, kind of like earning money to be able to buy that plane ticket to NYC. Then, individual cancer cells migrate away from the primary tumor, just like driving to the airport. Then, cells have to enter the circulation, just like passengers have to wade past security to get on the plane, a step called “intravasation”. Then the easy part, enter the blood circulation until you get to your destination, which in this case is a one-way ticket/flight to NYC. Then the cancer cells have to undergo “extravasation”, which is crossing past the endothelial cells, just like getting past border control and immigration officers at JFK Airport. then the cell has to find a way to live/adapt in this new environment/city, thus forming a metastatic colony or not.
I’m not sure if this analogy truly works, we’ll see!