General Information About Cancer

What Is Cancer?
Cancer occurs when cells in the body divide and grow abnormally.
Normally, cells throughout the body divide and grow as children's bodies develop, and as adult bodies replace old or injured cells. During this methodical system, new cells form, grow, and stop growing at the appropriate time. When cancer occurs, cell growth becomes uncontrolled. Often, but not always, these cancer cells form into a solid mass called a tumor. Not all tumors are cancerous, however: cancerous tumors are called “malignant,” while non-cancerous tumors are known as “benign.” If the cancerous cells are blood cells, as in leukemia, there is no solid tumor. Early detection and treatment are very important to increasing the patient's chances of recovery.
Cancer can occur in many parts of the body, and can take many different forms. The various forms can behave very differently from one another--they may grow at differing rates, and respond to treatments inconsistently. Cancer can also spread to other parts of the body through the bloodstream or lymphatic system (this is called metastasis), but the original site of the cancerous cells determines the cancer type.
What Causes Cancer?
The unusual cell growth that brings about cancer is the result of damage to DNA -- the substance inside all cells that directs cell behavior. Damaged DNA can be caused by genetics, by behavior (such as smoking or diet), or by things in the environment (such as air pollutants, radiation or occupational exposure to certain chemicals). Usually, the body can repair damaged DNA, but cancer cells evade this natural process.
Treating Cancer
Cancer is traditionally treated using three types of therapy: surgery, radiation, and chemotherapy. Depending on the type of cancer and its stage (how far the cancer has progressed), your doctor may use one of these methods or a combination of them in order to achieve the best possible result.
Today, in addition to these three approaches, new and promising therapies for cancer are being developed and used. These new approaches include gene therapy and immunotherapy, and may offer new hope to those who have not benefited from conventional treatment methods.
The City of Hope Approach
City of Hope, one of just 41 NCI-designated Comprehensive Cancer Centers in the United States, is dedicated to the prevention, treatment and cure of many different types of cancer. City of Hope has a world-class staff of researchers and physicians who are constantly developing new approaches to treating cancer.Last year, City of Hope conducted more than 300 studies enrolling more than 5,000 patients.
In just one example of our leading-edge research, City of Hope is the first – and currently only – institution in the world to perform a clinical study using genetically-engineered T-cells to recognize and attack glioma, a highly lethal (and unfortunately, quite common) form of brain cancer. Learn more about our treatment approaches.
Cancer Prevention
Through painstaking effort and years of research, scientists have been able to identify many of the causes of cancer. Today, it is believed that about 75 percent of cancer cases are tied in some way to how we live our lives. Since our lifestyle does contribute to the risk of having cancer, prevention often depends on knowing as much as possible about our own risk factors. It’s important to remember that cancer prevention is an ongoing process.
  • Carefully identify lifestyle factors such as smoking, dietary habits, or occupational hazards that might contribute to your risk of developing cancer.
  • Think about which of these lifestyle risk factors you can control.
  • Begin to make simple changes in lifestyle that may help lower your cancer risk. These changes often involve choices that are made every day.
  • The American Cancer Society recommends a cancer-related checkup every three years for people between the ages of 20 to 39 and annually for people age 40 or older.

Additional Information and Resources
This website is designed to provide information about the advanced treatment services and leading biomedical research available at City of Hope.
For general information on all types of cancers, as well as cancer causes and prevention, the National Cancer Institute ( and American Cancer Society ( are excellent sources.
Become a Patient
City of Hope is committed to making the process of becoming a patient here as easy as possible. Call 800-826-HOPE (4673) or complete the online appointment form.