Normal cells become cancer cells (malignant cells) when mutations in the DNA (deoxyribonucleic acid) sequence of a gene transform cells into a growing and destructive version of their former selves. These abnormal cells can then divide and multiply without control. Although DNA mutations can be inherited, it is much more common for DNA mutations to occur by one’s exposure to environmental toxins or from random cellular events. Under normal circumstances, the body repairs damaged DNA, but with cancer cells the damaged DNA is unable to be repaired.
The last few years have witnessed a dramatic increase in our understanding of inherited mutations (“germline” mutations) as important predisposing causes of aggressive prostate cancer. About 10% of prostate cancers are on the basis of inherited germline mutations. “Germline” mutations are DNA mutations that are inherited from one’s mother, father, or both parents. These inherited mutations have been present in every cell in the body since birth. This is as opposed to “somatic” mutations that are mutations that have occurred after birth and are not passed on to children. 90% of prostate cancer is thought to be due to non-inherited, acquired somatic mutations.