**2.3 Risk factors**

Several factors have been associated to hepatocellular carcinoma, being the most relevant viral hepatitis, alcohol, exposure to toxins and nonalcoholic fatty liver disease. In general, any etiology that causes chronic liver disease and that could lead to cirrhosis is a potential risk factor for primary liver cancer. It must be noted that hepatoma can very infrequently occur in the absence of cirrhosis as is the case of some individuals with chronic hepatitis B.
