All of the tissues and organs in the body (for example the skin, bones, glands, heart, and lungs) are made up of millions of cells. A chemical called deoxyribonucleic acid (DNA) makes up genes that are found in each cell. The genes contain the master plans and control the functions of the cell. For example, genes control which hormones (e.g., testosterone) and proteins a cell makes. Other genes control when the cell should multiply and others control when the cell should die.
Any damage to a person’s DNA, or impairment of the ability to repair damage to their DNA, can cause cancer and promote its growth.
One treatment approach that can stop the growth of rapidly dividing cancer cells is to give medications that damage their DNA. This can be effective because one fundamental defect of many types of cancer cells is that they lack the ability to repair breaks in their DNA strands.
One type of investigational medications being studied for the treatment of metastatic castration-resistant prostate cancer (mCRPC) that work by targeting the DNA repair process are the poly (adenosine diphosphate [ADP]-ribose) polymerase (PARP) inhibitors.
Rucaparib is a PARP inhibitor that is being studied for the treatment of mCRPC by Clovis Oncology. Rucaparib has not been approved by any regulatory body, including the FDA, for the treatment of patients with prostate cancer. Rucaparib is thought to work by targeting key proteins (PARP) involved in the DNA repair process. Cancer cells undergo rapid DNA replication, therefore, mistakes in their DNA sequence can quickly accumulate if they are not repaired, leading to tumor cell death. Rucaparib is being studied to evaluate its effect in men with mCRPC with alterations in the breast cancer (BRCA) and ataxia telangiectasia mutated (ATM) genes. Other genetic markers that are being studied to determine if they can identify men with prostate cancer who may respond to rucaparib include BARD1, BRIP1, CDK12, CHEK2, FANCA, NBN, PALB2, RAD51, RAD51B, RAD51C, RAD51D, and RAD54L.
Such alterations in DNA-repair genes can be detected with tests that physicians can perform on DNA from prostate cancer cells. Some alterations can also be detected with a blood test.
For more information about genetic testing in cancer visit the National Cancer Institute website: