WEDNESDAY, Dec. 7 (HealthDay News) -- Scientists have long noted a link between chronic hepatitis C infection and an increased risk for liver cancer, and a new study may help explain why.

"What we've found is that one of the hepatitis C virus proteins (NS5B) targets a cell protein (retinoblastoma) that is crucial for suppressing the development of tumors, interfering with its ability to control cell proliferation," senior author Dr. Stanley M. Lemon, of the University of Texas Medical Branch at Galveston, said in a prepared statement.

"By knocking out this 'tumor suppressor' and promoting the proliferation of liver cells, this rival protein is setting up the liver for cancer," Lemon explained.

The study appears this week in the early online edition of the journal Proceedings of the National Academy of Sciences.

It has long been known that hepatitis C infection can lead to liver cancer, but it wasn't known how the virus actually worked to promote liver cancer.

"The way that NS5B docks with the retinoblastoma protein is biochemically almost identical to the way a protein made by human papilloma virus (HPV) does so to produce similar cancer-promoting results," Lemon said.

Experts consider HPV infection to be the leading cause of cervical cancer.

The parallel is "interesting," Lemon said, "because the two viruses are so different -- HPV is a DNA virus, while hepatitis C is composed of RNA."

These new findings may help in the development of improved treatments for people infected with hepatitis C in order to prevent liver cancer, he said.

More information

The American Cancer Society has more about preventing liver cancer.