Scientists hope new technology will help them develop a blood test to improve early diagnosis of liver cancer in high risk groups.
Scientists have measured protein levels
A team at the University of Birmingham used sophisticated protein measurement and computer analysis to detect changes characteristic of early liver cancer.
The discovery could potentially save lives as liver cancer treatment is more effective if started early.
Details are published in the British Journal of Cancer.
About 2,500 people are diagnosed with primary liver cancer in the UK each year
The major risk factors are infection with hepatitis B and C and consumption of foods contaminated with aflatoxin
Hepatitis B is more common and the distribution of this infection worldwide largely explains differences in rates of liver cancer
Cancer which first arises in the liver, or hepatocellular carcinoma, is the sixth most common cancer in the world, being especially widespread in East Asia.
High-risk groups, such as people with cirrhosis of the liver, are monitored currently - but tests are not sensitive enough to detect the disease early.
Lead researcher Professor Philip Johnson said: "We have shown that the right combination of technology and computer analysis can 'break the code' of liver cancer and distinguish people with early liver cancer from those without the disease.
"Our method was more accurate than the existing liver cancer blood test.
"However, this is only the first step on a long road towards a test that can be reliably used for the many people at risk of developing primary liver cancer.
"We want to improve the technology to make the test even more accurate."
Liver diseases, including cirrhosis and hepatitis from the hepatitis B and C viruses, greatly increase the risk of hepatocellular carcinoma.
Although vaccinations against the hepatitis B virus are now administered to children in most countries of the world, there are millions of people already infected for whom vaccination would be too late.
And as there is no effective vaccination for hepatitis C, the global incidence of liver cancer is going to remain high for several decades.
The current methods used to monitor such high-risk groups include ultrasound scans and a test for the presence of a single protein in the blood called alpha-fetoprotein.
It is a good indicator of advanced liver cancer, but less able to detect early disease.
Professor John Toy, of Cancer Research UK, said: "More work is needed to prove that patterns of protein levels associated with liver cancer can be used as a reliable test for monitoring high-risk groups."