Liver cancer vaccine effective in mice

Tweaking a protein expressed by most liver cancer cells has enabled scientists to make a vaccine that is exceedingly effective at preventing the disease in mice.

Alpha-Fetoprotein, or AFP - normally expressed during development and by liver cancer cells as well - has escaped attack in previous vaccine iterations because the body recognizes it as "self," said Dr. Yukai He, immunologist at the Medical College of Georgia and Georgia Regents University Cancer Center.

Liver cancer is among the fastest-growing and deadliest cancers in the United States with a 17 percent three-year survival rate. Vaccines help direct the immune system to attack invaders by showing it a representative substance, called an antigen, that the body will recognize as foreign, in this case, AFP for liver cancer.

In a process called antigen engineering, He tweaked AFP just enough to get the immune system to recognize it but still keep the AFP expressed by liver cancer cells in the bull's eye, he and his colleagues report in the journal Hepatology.

AFP is expressed by about 80 percent of most common liver cancer cells but not typically by healthy adults. For cancer to flourish, cells must revert to an immature state, called dedifferentiation, which is why liver cancer cells express a protein during development and why the immune system can recognize AFP as "self."

He's modified AFP was delivered in a vehicle with a proven record for getting into cells. The lentivector is the backbone of the human immunodeficiency virus, or HIV, minus most of its genes. It is particularly good at targeting dendritic cells, whose job is to show the immune system antigens then activate T cells to attack.

Georgia Regents University liver cancer vaccine promising With liver cancer rates rising in the U.S. along with obesity and diabetes rates, an experimental vaccine at Georgia Regents University Cancer Center is proving effective in animals and researchers are hoping to speed it along to human trials.

Dr. Yukai He, a Georgia Research Alliance Distinguished Vaccine Investigator at the cancer center, has a $1.6 million grant from the National Cancer Institute to further refine his vaccine approach against hepatocellular carcinoma, which the American Cancer Society said accounts for 80 percent of liver cancers.

Those kinds of cancers are a particular problem as liver cancer rates have tripled during the past 30 years, he said.

“It’s really dramatic,” He said. “There is no cancer that has increased so dramatically this way.”

While some of it is likely due to increasing rates of Hepatitis C and Hepatitis B infections, rising rates of obesity and diabetes are likely to blame for 60 percent of the increase, he said. It’s not clear exactly how those diseases cause liver cancer but it could be that they induce chronic inflammation and damage in the liver, similar to what the viruses inflict, that cause cell mutations that lead to cancer, He said.