A risk factor is anything that may increase your chance of having a disease. Risk factors for a certain type of cancer might include smoking, diet, family history, or many other things. The exact cause of someone's cancer may not be known. But risk factors can make it more likely for a person to have cancer.

Things you should know about risk factors for cancer:

• Risk factors can increase a person's risk, but they don't always cause the disease.
• Some people with risk factors never develop cancer. Other people with cancer have no risk factors.
• Some risk factors are very well known. But there's ongoing research about risk factors for many types of cancer.

Some risk factors, such as family history, may not be in your control. But others may be things you can change. Knowing the risk factors can help you make choices that might help lower your risk. For instance, if an unhealthy diet is a risk factor, you may choose to eat healthy foods. If excess weight is a risk factor, you may decide to try to lose weight.

Anyone can get mesothelioma. But there are some factors that can increase your risk for this type of cancer.

Asbestos exposure is linked to most cases of mesothelioma.

Asbestos is a mineral fiber found in certain types of rock. In the past, asbestos was common in cement, insulation, ceiling and floor tiles, roof shingles, automotive parts, and patching compounds. It's no longer used in most of these products in the U.S. But it's still in some places, such as in the building materials and insulation in older homes.

If asbestos fibers are breathed in, they can travel to the lining of the lungs and harm the cells there. This damage might lead to cancer. People who worked with asbestos for a long time are most likely to be at risk. This includes some miners, factory workers, construction workers, and insulation manufacturers or installers. It also includes ship construction workers, railroad or automotive workers, and others exposed to asbestos at work. Family members of these workers could also be exposed to asbestos if it's brought home on clothing.

People who have been treated for another cancer with high doses of radiation to the chest or belly (abdomen) may be at higher risk for mesothelioma. Still, this is rare.

Your risk of this cancer goes up as you get older. It's most common in people age 65 or older.

Men are more likely to get mesothelioma than women. This may be because men are more likely to work at jobs where they're exposed to high levels of asbestos.

Zeolites are a group of minerals that are like asbestos. They're common in the soil and rocks in certain parts of the world. They've been found in Nevada, Oregon, Utah, Arizona, Montana, and South Dakota. Breathing in these fibers can increase the risk for mesothelioma.

Changes (mutations) in the BAP1 gene have been linked to mesothelioma. This mutation is passed in families, and it's very rare.

Talk with your doctor about your risk factors for this cancer. Ask what you can do about them. Some risk factors, such as your age, aren't under your control. But there are some things you can do that might lower your risk.

For instance, it's important to limit your exposure to asbestos. Most people aren't exposed to large amounts of asbestos. But this can be more of a concern for people who work in certain industries. These include construction or textile manufacturing. You may need to wear protective clothing, an approved respirator, or other safety equipment. If you have questions, contact one of these government resources:

• National Institute for Occupational Safety and Health (NIOSH) at 800-CDC-INFO (800-232-4636) or www.cdc.gov/niosh
• Occupational Safety and Health Administration (OSHA) at 800-321-OSHA (800-321-6742) or www.osha.gov

Many older homes and other buildings might have materials that contain asbestos. In general, this isn't a concern as long as the fibers aren't disturbed, such as during remodeling. If you think products that contain asbestos may have been used in your home, ask an expert to check your home. If you have a home with asbestos, don't disturb it or try to remove it yourself. Asbestos doesn't always have to be removed. If needed, hire a qualified asbestos expert to check and remove asbestos in your home.

Screening is the process of looking for cancer in people who don't have symptoms. Screening for mesothelioma in the general population isn't advised by any major medical organization in the U.S. at this time.

Still, if you've been exposed to large amounts of asbestos, talk with your doctor. Or they may raise the idea of screening with you. Some doctors might suggest tests to look for early signs of this cancer. These might include CT scans or X-rays of the chest or certain blood tests. But not all doctors agree that these tests are useful.