Review article: steatosis, the metabolic syndrome and cancer.

The incidence of hepatocellular carcinoma is increasing, but the temporal changes of risk factors remain unclear. A significant proportion of hepatocellular carcinoma (7-30%) develops in cryptogenic cirrhosis, and may represent the most worrisome complication of non-alcoholic steatohepatitis. Non-alcoholic steatohepatitis is tightly related to insulin resistance and several features of the metabolic syndrome, i.e obesity, type 2 diabetes and dyslipidaemia. Nearly two-thirds of adults in the United States and an increasing percentage of the population worldwide are overweight or obese. Diabetes prevalence is increasing as well. The rising prevalence of risk factors associated with non-alcoholic steatohepatitis can partially account for the increasing incidence of cryptogenic cirrhosis and subsequent hepatocellular carcinoma. Moreover, recent evidence demonstrates that both obesity and diabetes are per se associated with an increased cancer risk. Large prospective studies show a significant association with obesity for several cancers, including cancers of the colon, female breast, endometrium, kidney, oesophagus and liver (hepatocellular carcinoma). Type 2 diabetes is also related with increased risks of colon, endometrial, kidney, pancreatic cancer and hepatocellular carcinoma. In western countries, the insulin resistance syndrome is emerging as a risk factor for a wide variety of cancers, including hepatocellular carcinoma.