This process is called angiogenesis. By blocking the development of new blood vessels, researchers are hoping to cut off the tumor's supply of oxygen and nutrients and therefore its continued growth and spread to other parts of the body. Scientists know that many things can damage genes, including carcinogens , viruses , heredity , or the aging process. Others thought that viruses caused tumors to develop. In the 1980s, it was determined that both carcinogens and viruses can produce cancer genes - also called oncogenes .
Oncogenes get their name from the Greek word 'onkos', which means lump or mass.
Researchers know that cancer cells are unresponsive to the usual signals that control the growth of normal cells. If the genes that help maintain the repair of DNA are lost or not functioning, the likelihood that a damaged gene will be repaired decreases drastically. Tumor cells often have defects in the way DNA gets repaired Scientists have started to find ways to change patients' genetic material to fight or prevent disease. Gene therapy is the process of supplying cells with healthy copies of missing or flawed genes . With this approach, the genetic makeup of the patient's cells is corrected, instead of giving the patient drugs to treat or control the disease.