Cancer is caused by mutations in the DNA of our cells. These mutations can come about by chance, or can be caused by environmental factors, and result in cells multiplying out of control. We know that different DNA mutations can cause different types of cancer. For example, mistakes in the BRCA1 and BRCA2 genes are known to have a role in breast and ovarian cancer development. However, despite decades of research, we don’t yet understand why these errors only cause cancer in specific organs, and not in other parts of the body. The faulty genes can be found in nearly all our cells – so why is the cancer found in specific places?