The process of mitosis is one of the main reasons why cancer exists. Cells go through many stages to create an exact replica of themselves. Cancer all starts off with a single cell turning into a cancerous cell, caused by a mutation in the cell’s DNA, affecting its growth.
Once this cancer cell is created, it multiplies faster than a normal cell. Many cancer cells form into what’s called a tumor. Some of the cancer cells will break off of the tumor and flow through the body’s bloodstream, creating more tumors throughout your body, this process is called metastasis. The ‘normal’ cells in your body will multiply a certain number of times, and then they’ll die. Cancer cells of the other hand will continue to reproduce, as long as they have a source of food oxygen.
This image shows the process of normal cell division (on the left), the cells are dividing slowly and in the end the cell dies. And the much more sped up process of cancer cell division (on the right), the cells just keep on dividing over and over again.
The video above is explaining how the cell cycle relates to cancer.
Cell Cycles Modeling Project 