The candidate liver cancer biomarker is Golgi Protein-73 (GP73), which was first discovered in Dr. Fimmel’s lab in 1998. Subsequent studies have shown that the blood levels of GP73 are consistently higher in patients with liver cancer than in healthy individuals. In addition, levels were not significantly higher in patients with diseases other than liver disease. We are on the verge of understanding what switches GP73 on and how we can use it for diagnostic purpose.
Liver cancer is the fifth most common cancer in the world and one of the deadliest cancers since it is rarely diagnosed until late in its development.
The current blood test used to screen for early tumors in people at high risk for liver cancer involves a protein called alpha-fetoprotein (AFP), Fimmel said. Patients who are at risk for liver cancer typically have chronic liver disease such as cirrhosis due to infection with the hepatitis B or C virus or alcoholism.
“Unfortunately, the AFP test is not good enough to detect liver cancer in time, and it often generates a false positive in patients who end up not having the cancer,” Fimmel said.
The blood samples of more than 1,000 patients with various stages of liver and non-liver disease have been tested for the presence of GP73 in several studies around the world. Several medical diagnostic companies are in the process of developing automated serum tests for the protein that could be performed in routine hospital laboratories.
“GP73 is currently being test in clinical trials in a couple of places. The biggest study is being done in China where liver cancer is very common due to the large numbers of people infected with hepatitis B,” Fimmel said.
With the large number of Americans infected with hepatitis C, the number of people developing cirrhosis in the United States is expected to rise during the next 20 years.
“If you have cirrhosis, each year you have a 1 to 2 percent higher chance of developing liver cancer. Each year it goes up a notch,” Fimmel said. “Consequently, a person has as much as a 20 percent risk for developing liver cancer after having cirrhosis for 20 years.”