Nearby tissue reveals liver cancer recurrence risk

BOSTON (Reuters) - The key to whether liver cancer is curable may lie not with the tumor, but in the apparently healthy liver cells surrounding it, scientists said on Wednesday.

An international research team reported that it has identified 186 bits of genetic material whose activity levels in surrounding tissue predict whether hepatocellular carcinoma, a form of liver cancer, is likely to reappear.

"What we found was that the information to predict future recurrence wasn't in the primary tumor itself, but was in the surrounding non-tumor liver tissue, which suggests that the so-called recurrences aren't really recurrences," Dr. Todd Golub, one of the researchers, said in a telephone interview.

"They're really new primary tumors that are arising in a liver that has been damaged, as opposed to the old tumor just coming back," added Golub, who heads the cancer program at the Broad Institute of the Massachusetts Institute of Technology and Harvard University.

The findings, published in the New England Journal of Medicine, could someday lead to a test that tells doctors which patients require aggressive treatment after surgery.

Liver cancer is the third-leading cause of cancer deaths worldwide.

The discovery grew out of an effort to find a way to look for genetic links to diseases using tissue preserved in a solution of formaldehyde. Until now, doctors had to use frozen tissue because formaldehyde chops up the genetic material needed for the analysis.

But a new technique, developed by Illumina Inc in San Diego, allows researchers to analyze the genetic material even though it has been broken up by the formaldehyde.

Because formaldehyde preservation has been around for decades, the new technique allows doctors to use tissue samples taken many years ago to look for genetic signatures in cases where they already know the outcome.

That could help speed the development of new drugs, Golub said.

"Rather than say we're going to treat all liver cancer patients with a new drug that holds promise to prevent future recurrences, let's focus on the subset of patients who are highest risk," he said. "If you're at low risk for recurrence it's probably not worth being exposed to the potential side effects of a new treatment."

In the new study, the researchers were able to look for gene patterns in liver cancer cases from New York, Tokyo, Milan and Barcelona going back as far as 24 years.

(Editing by Will Dunham and Eric Beech)