How does Cancer Grow?

Cancer grows like a bad weed. Left unchecked, cancer has 2 means to progress by proliferation. First it speeds the time to split in two and second they send seeds to start a new cancer elsewhere: metastatic cancer.
1. Speed it up. Cancer is a freak speeder, its growth is exponential. Meaning everything the cells split to get 2. So imaging a cancer cell that has a speed rate of 24 hours, one day, in one month if at all stay alive you get more than a trillon cells.
2. Spread it up. Proliferation is a complex process, but the key element is the connection between growth factors on the cell surface and a multitude of protein signaling pathways inside the cell. Cancer cells learn to produce their own growth factors which bypass the normal and tightly controlled cell division. That process gives rise to the progression of oncogenic transformation and tumorigenesis.