Updated on September 18, 2026.
The liver is the body’s largest solid organ and performs over 500 functions.
This organ is sometimes called “the body’s chemical factory” because it produces multiple substances that are critical to the body’s health and function. These include digestive bile, blood clotting factors, cholesterol (needed to build cells and hormones), and albumin (a main component in blood plasma, the liquid part of blood).
The liver also acts as a filter. As blood moves through the liver, this organ breaks down unwanted or unneeded substances, including cellular waste products, medications, and alcohol.
What is liver cancer?
Liver cancer refers to cancers that begin in the liver. (This does not include cancers that begin somewhere else in the body and spread to the liver. Cancers are named for the site where they originate).
Like other cancers, liver cancers occur when cells become abnormal or damaged and begin to grow out of control. The majority of liver cancers are hepatocellular carcinoma (HCC), which account for 80 to 90 percent of cases. HCC begins in cells called hepatocytes, which are the main type of cell in the liver.
A smaller percentage (between 10 and 20 percent) of liver cancers are intrahepatic cholangiocarcinoma (IHC). IHC originates in bile ducts inside the liver. Bile ducts are tubes that transport bile, a digestive fluid produced by the liver. There are also rare types of liver cancers that account for a small percentage of cases.
In the United States, liver cancer is less common than it is in other parts of the world, but rates have been increasing in recent decades.
What are the risk factors for liver cancer?
The most common risk factors or causes associated with HCC are underlying diseases or infections that affect the liver. These risk factors include:
- Hepatitis C infection. This is a chronic viral infection that causes inflammation in the liver and can lead to cirrhosis (scarring and hardening of liver tissue).
- Hepatitis B infection. Another chronic viral infection that can damage the liver. Hepatitis B can also lead to HCC before cirrhosis occurs.
- Metabolic dysfunction-associated steatotic liver disease (MASLD). A disorder where fat accumulates in the liver. It is associated with type 2 diabetes, overweight, obesity, and rare genetic metabolic disorders, which are all risk factors for liver cancer on their own.
- Heavy alcohol use. Heavy alcohol use can damage the liver, leading to cirrhosis and liver cancer. The risk of liver cancer increases significantly when heavy alcohol use is combined with a hepatitis B or C infection.
- Autoimmune hepatitis. Autoimmune diseases are disorders where the body’s immune system attack and damage healthy tissue. Autoimmune diseases that attack the liver can cause cirrhosis and increase the risk of liver cancer.
- Tobacco use. Smoking increases the risk of HCC, as well as many other types of cancers and serious chronic illnesses, including chronic obstructive pulmonary disease (COPD) and cardiovascular disease.
Risk factors for bile duct cancer (IHC)
IHC shares the same risk factors as HCC, as well as several others, including:
- Parasitic infections of the bile ducts
- Bile stones
- Bile duct cysts
- Primary sclerosing cholangitis, a rare disease that causes narrowing of the bile ducts
- Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn’s disease
Industrial chemical exposure
HCC and IHC have also been associated with exposure to certain industrial chemicals, including vinyl chloride. Vinyl chloride is more often associated with a rare type of liver cancer called hepatic angiosarcoma, which originates in the blood vessels or lymph vessels in the liver.
Aflatoxins
This is a carcinogen (cancer-causing agent) found in fungus that can grow on certain foods, including corn, peanuts, and tree nuts. This typically occurs when these foods are stored in a warm, humid environment. It is more common in tropical or subtropical regions, but also occurs within the U.S.
Aflatoxins can also contaminate livestock feed and products made from contaminated foods (like seed oils and nut butters). The U.S. Food & Drug Administration regularly tests susceptible foods for aflatoxin contamination with strict allowances for levels.
If you have concerns about your risk of liver cancer, want to know if you should be screened for liver cancer, or have questions about a diagnosis, a healthcare provider will be your best source of information.
