Science and Health

Scientists use arsenic to fight blood cancer

(China Daily)
Updated: 2010-04-10 08:57

SHANGHAI: Scientists in China have demonstrated how arsenic, a popular poison in the Middle Ages, fights blood cancer by targeting and killing specific proteins that keep the disease alive.

"Our study showed how arsenic directly targets these proteins and kills them," said lead researcher Zhang Xiaowei at the State Key Laboratory of Medical Genomics in Shanghai.

"Unlike chemotherapy, the side effects of arsenic in treating acute promyelocytic leukemia (APL) are very low," Zhang said.

"There is no hair loss or suppression of bone marrow function. We are interested in finding out how arsenic can be used in other cancers."

Known for its toxicity, arsenic was regarded as a top poison because its symptoms are like those of cholera and can often go undetected.

But it has long served a dual purpose in China. Apart from poisoning, it has been used for at least 2,000 years in traditional Chinese medicine.

In 1992, a group of Chinese doctors reported how they used arsenic for APL, a blood and bone marrow cancer that has surprisingly high cure rates of more than 90 percent in China.

However, the actual workings of arsenic and how it interacts with cancer tissues has never been clear - until Zhang and his colleagues used modern technology to find out.

In a paper published in the journal Science, Zhang and his team, which includes Health Minister Chen Zhu, described how they used modern equipment and saw how arsenic attacked specific proteins that would otherwise keep the cancer alive.

"This shows how Western technology can be used to find out about the mysteries of Chinese medicine," Zhang said.

"Although many countries are now using arsenic to treat APL, some countries are resistant to the idea. It depends a lot on whether doctors recommend it and whether patients accept it."

"Arsenic treatment has long been considered effective for various types of leukemia," said Yan Xiaojing, a researcher at the laboratory.

"Our study explained the working mode by identifying a specific protein as a direct target of arsenic trioxide - evidence in the support of arsenic's validity in treating APL," Yan told China Daily on Friday.

In APL, there is a drop in the production of normal red blood cells and platelets, resulting in anemia and thrombocytopenia. The bone marrow is unable to produce healthy red blood cells. Until the 1970s, APL was 100 percent fatal and there was no effective treatment.

"The clinical result of arsenic in treating APL is well-established. More than 90 percent of APL patients in China have (at least) five years of disease-free survival," Zhang said.

In a separate commentary in Science, Scott Kogan at the cancer center of the University of California, San Francisco, wrote that proper case selection and combination therapy with arsenic may lead to improved outcomes for treating not only promyelocytic leukemia, but other diseases as well.

"If so, an ancient medicine, revived through careful clinical and biological studies in modern times, will have an even greater impact on human health," wrote Kogan, who was not linked to the Chinese study.

Reuters contributed to the story.

China Daily