New research into the link between obesity and liver cancer, led by Peter Mac and Monash University, has indicated patients won't always develop serious liver diseases as a precursor to cancer.

The research was led by Professor Tony Tiganis who is Head of the Cancer Metabolism Program at Peter Mac and holds a joint appointment at the Monash Biomedicine Discovery Institute where he heads the Metabolic Disease, Diabetes and Obesity Program.

It has been understood obese people most at risk of liver cancer will develop non-alcoholic fatty liver disease (NALFD) and the more severe non-alcoholic steatohepatitis (NASH), leading to cirrhosis and liver failure,  and then possibly cancer (hepatocellular carcinoma, HCC). Current guidelines in Europe and the US restrict the testing for liver cancer in obesity to patients with cirrhosis only.

"What this research has shown is that the current screening for liver cancer in obese patients is potentially missing a group of at-risk people. Until now, we have believed that the lack of development of serious liver disease has meant certain groups are unlikely to develop the deadly cancer,” Prof Tiganis says.

“If having NASH or cirrhosis are not the only pathways for the development of liver cancer in obese people, we urgently need to develop biomarkers to help identify those NAFLD patients that may be at risk of developing HCC.”

The research indicates liver cancer can be triggered in obese mice via a completely separate molecular pathway than that which leads to NASH-cirrhosis.

The obesity-NASH-cirrhosis pathway is driven by the triggering of a protein called STAT-1, however mice who developed liver cancer without developing NASH had their cancers triggered by a different protein STAT-3.

There are drugs approved for use in other diseases which target these pathways, however Professor Tiganis cautions it is too early to assume that these could be used to prevent liver cancer in people who are obese.

The research used animal models and human tissue biopsies provided by Prof Wendy Brown and her team from the Monash University Department of Surgery, and the findings are published in the journal Cell.

Liver cancer is the fifth most common cancer worldwide and the third most common cause of cancer death. Over the last 20 years, the incidence of liver cancer has doubled in the United States (US) and tripled in Australia. The obesity epidemic accounts for 30-40 per cent of this increase in liver cancer.

Read the research paper in full here - Obesity drives STAT-1-dependent NASH and STAT-3-dependent HCC.