A human gene that causes leukemia and prevents liver cancer

Scientists at the University of California, San Diego School of Medicine, and the Eastern Hepatobiliary Surgery Hospital in China have said that a human gene implicated in the development of leukemia also acts to prevent cancer of the liver.

Gen-Sheng Feng, UCSD professor of pathology, and colleagues in San Diego, Shanghai and Turin reported that an enzyme produced by the human gene PTPN11 appears to help protect hepatocytes (liver cells) from toxic damage and death. Conversely, the same enzyme, called Shp2, is a known factor in the development of several types of leukemia.

"The new function for PTPN11/Shp2 as a tumour suppressor in hepatocellular carcinoma (HCC) stands in contrast to its known oncogenic effect in leukemogenesis," said Feng.

"It's a surprising finding, but one that we think provides a fresh view of oncogenesis. The same gene can have oncogenic or anti-oncogenic effects, depending upon cellular context," added Feng.

"The liver is a most critical metabolic organ in mammals, including humans," said Feng.

"It has a unique regenerative capacity that allows it to resist damage by food toxins, viruses and alcohol. Shp2 normally acts to protect hepatocytes. Removing Shp2 from these liver cells leads to their death, which in turn triggers compensatory regeneration and inflammatory responses.

That results in enhanced development of HCC induced by a chemical carcinogen," added Feng.

The study is detailed in journal Cancer Cell.