Cancer is a disease that starts when cells in your body start to grow out of control. They may not die when they should, or they might continue to grow even though they are damaged or abnormal. Cancer can also spread to other parts of the body, where it can affect how your organs work. There are many different types of cancer, and each one can grow and spread in a slightly different way. In some cases, the type of cancer can help doctors decide how best to treat it.

Experts don’t know what causes most cancers. But they do know that some cancers are linked to things you can avoid, such as smoking and certain infections. Other cancers can be caused by genes that you inherit from your parents. And some cancers are linked to lifestyle habits, like eating a healthy diet and getting enough sleep.

Your body is made up of trillions of cells that over your lifetime normally grow and die as needed. But when something goes wrong with your cells, the abnormal ones can keep growing and crowd out the normal ones. This can cause the tissue to become inflamed, and you might feel pain or notice a lump or bump. Some cancers can also destroy your blood vessels, which can prevent the body from getting the oxygen and nutrients it needs to function.

Scientists have identified six features that cancer cells share. They can’t happen all at once, but over time these features make cancer cells different from normal cells.

In addition, cancer cells don’t use the proteins that regulate cell growth. Instead, they rely on other ways to get energy and grow. They often have double the normal number of chromosomes or have mutations (changes) in the chromosomes that contain instructions for how cells should grow and develop. They also produce more proteins that can help them grow and spread, and they don’t respond to signals from the body that stop a cell from growing.

Another feature that sets cancer cells apart from normal cells is that they can often grow and multiply without stopping if the environment around them is right. This includes the presence of certain chemicals, known as carcinogens, which can cause cancer if you are exposed to them for long periods of time.

In general, you can reduce your risk of developing cancer by living a healthy lifestyle. For example, regular exercise is good for your overall health and can help you maintain a healthy weight. This can help protect you from some cancers, including breast and colon cancers. You should also limit your alcohol intake. Although it doesn’t increase your risk of all cancers, drinking too much alcohol raises your risk of some types, including those of the lungs, liver and colon. If you are a heavy drinker, talk to your doctor about how to cut back or quit drinking completely. Regular cancer screenings are also important, especially for people at higher risk for some cancers.