We do not know exactly what causes prostate cancer. But researchers have found some risk factors and are trying to learn just how these factors cause prostate cells to become cancerous.
On a basic level, prostate cancer is caused by changes in the DNA of a prostate cancer cell. During the past few years, scientists have made great progress in understanding how certain changes in DNA can cause normal prostate cells to grow abnormally and form cancers. DNA is the chemical that carries the instructions for nearly everything our cells do. The reason that you might look like your parents is because they are the source of your DNA.
DNA affects more than the way you look. Some genes (parts of your DNA) contain instructions for controlling when cells grow and divide. Certain genes that promote cell growth and division are called oncogenes. Others that normally slow down cell division or cause cells to die at the right time are called tumor suppressor genes. Cancer can be caused by DNA changes (mutations) that turn on oncogenes or turn off tumor suppressor genes.
DNA changes can either be inherited from a parent or can be acquired during a person's lifetime.
For full text: [Do we know what causes prostate cancer? | American Cancer Society]