During the past few years, scientists have made great progress in understanding how certain changes in a person's DNA can cause cells to become cancerous. DNA is the chemical in each of our cells that makes up our genes -- the instructions for how our cells function. We usually look like our parents because they are the source of our DNA. However, DNA affects more than how we look. It also can influence our risk for developing certain diseases, such as some kinds of cancer.

Some genes contain instructions for controlling when cells grow and divide. Genes that promote cell division are called oncogenes. Genes that slow down cell division or cause cells to die at the right time are called tumor suppressor genes. Cancers can be caused by DNA changes that turn on oncogenes or turn off tumor suppressor genes.

Some people with cancer have DNA changes they inherited from a parent that increase their risk for the disease. Usually, however, these DNA changes are acquired during life rather than inherited before birth.

Scientists have found several changes in oncogenes and tumor suppressor genes in cells from eye cancers such as melanoma and lymphoma. However, they are still not certain why these changes occur in some people, exactly how the changes occur, and how the changes might cause or promote cancer formation.

Last Medical Review: 03/03/2009
Last Revised: 05/14/2009