Imagine this: a doctor says to a cancer patient that a gene in their body is responsible for their leukemia. Now imagine that the doctor tells the patient that the gene can be suppressed, but that suppressing the gene could cause liver cancer.
According to scientists at the University of California, San Diego (UCSD) the gene PTPN11 – a gene responsible for determining the type of cell, cellular growth or the formation of cancerous cells – plays an important role in the prevention of liver cancer, while sometimes being responsible for leukemia.
“We noticed that when PTPN11 is removed from hepatocytes, a type of liver cells, cancer development is dramatically increased. This suggests that PTPN11 normally acts to prevent liver cancer,” said Gen-Sheng Feng, professor of pathology and molecular biology at UCSD.
Feng and his colleagues – based in San Diego; Shanghai, China and Turin, Italy – used an advanced scientific technique to allow them to take a closer look at PTPN11.
The researchers deleted genes from specific types of cells in mice and observed the results.
Feng said that he and his colleagues were surprised at the revelations that the absence of the gene PTPN11 could be a cause of liver cancer.
“Our group has been interested in studying the function of the gene PTPN11 in liver regeneration, a very important physiological process in protecting the liver against damages triggered by food toxins, viruses and alcohols,” Feng said.
He said that people should not think of the gene like kids think of programs on Cartoon Network, where the good guy and the bad guy are clearly identifiable. Feng said that this very simplistic way of looking at PTPN11 should be avoided because people need to realize that there are good aspects and bad aspects of genes and that nothing is perfect.
“For a gene of critical importance in life and health, it will cause problems when it is overly-active or when it has no function,” Feng said. “We need to understand the good and bad aspects of things.”
The gene causes leukemia when it is overly active, but Feng warns against drastic action that could lead to liver cancer.
“Doctors need to be very careful in what they do in their attempts to suppress this gene because it normally has a tumor suppressor function in liver cancer,” Feng said.
Shuangwei Li, researcher at the department of pathology at UCSD, was also taken aback by the results of their research.
“We didn’t expect something like this. We didn’t know that PTPN11 would act as a tumor suppressor in liver cancer,” Li said.
He said that the survival of the hepatocyte is severely hampered by the removal of the gene, due to the inability of cells to re-grow after being affected by cancer.
“The liver grows back slower and as much as two-thirds of the liver can be impaired,” Li said.
Along with leukemia, liver cancer continues to be problematic in the United States. The National Cancer Institute reported 24,120 new cases of liver cancer and 18,910 deaths as a result of liver cancer in 2010.
However, with the new research coming from Feng and his colleagues, doctors may soon know more about liver cancer.
“We hope to see an impact of our research work very soon, but it is very hard to predict when it can have an impact,” Feng said. “As long as we keep working on it, a breakthrough will happen; we will make progress in research which can change the world.”
ERIC C. LIPSKY can be reached at science@theaggie.org.
