IANS

Washington, Oct 22: Aflatoxin which is produced by mould on nuts and grains can trigger liver cancer if consumed in large quantities, besides endangering 4.5 billion of the world's poor with its deadly effects, say scientists.

"It's shocking how profoundly these moulds can affect public health," said Sheryl Tsai, University of California-Irvine (UC-I) and lead study author.

In places like China, Vietnam and South Africa, the combination of aflatoxin and hepatitis B virus exposure boosts liver cancer risk by 60 times, and toxin-related cancer causes up to 10 percent of all deaths in those nations.

Tsai, students Tyler Korman and Oliver Kamari-Bidkorpeh, along with Johns Hopkins University researchers, found that a protein called PT is critical for aflatoxin to form in fungi. Previously, scientists didn't know what prompted the toxin's growth.

"The protein PT is the key to making the poison," Tsai said. "With this knowledge, perhaps we could kill the PT with drugs, inhibiting the mould's ability to make aflatoxin."

Destroying the mould -- rather than just the PT -- is the traditional method of decontamination, but it's expensive, costing hundreds of millions of dollars worldwide.

Aflatoxin can colonize and contaminate nuts and grains before harvest or during storage. The toxin wreaks havoc on a cancer-preventing gene in humans called p53.

Without p53 protection, aflatoxin can compromise immunity, interfere with metabolism, and cause severe malnutrition and cancer.

"This finding will lead to an increased understanding of how aflatoxin causes liver cancer in humans," a UC-I release said.

The study was published in the Thursday edition of Nature.