2006年VOA标准英语-Researchers Cure Lethal Cancer in Mice（在线收听）

By Jessica Berman
Washington
08 May 2006
 
Scientists report they have cured a highly malignant form of cancer in ordinary laboratory mice using the white blood cells of mice that are resistant to cancer. Scientists say while the research holds promise, a cure for human cancer may be a long way off.

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A cancer-resistant mouse in one of the rooms housing the colony   
  

In an early online publication of Proceedings of the National Academy of Sciences, researchers at Wake Forest University in North Carolina describe how the white blood cells of a strain of the mighty, cancer resistant mice, injected into normal mice with aggressive cancer, completely cured the rodents.

"You can actually see these events," said Zheng Cui, the study's lead author. "The tumor cells get attacked by these immune cells, and then they just swell like a balloon and then eventually just pop."

In a prior study, researchers reported that white blood cells from the cancer resistant mice protect normal mice exposed to cancer causing substances.

In addition, Cui says mice cured of cancer remain cancer- free.

The story of the mighty mice began in 1999 when the scientists injected laboratory mice with a variety of substances so they could study them.

All of the mice developed cancer except for a single rodent, according to tumor biologist Cui.

"We said probably maybe we made a mistake or the injection was bad," he said. "And then we kept injecting him, but he just refused to grow cancer."
 

Dr. Zheng Cui and Dr. Mark Willingham  
  
Cui and colleagues bred the mouse and, much to their surprise, half of its offspring were also completely resistant to any form of cancer development. So far, researchers have at least 2,000 mice with the trait.

For reasons scientists are trying to understand, the mice possess a mutation that stimulates an immediate, extremely aggressive immune reaction against the cancer.

White blood cells that are normally charged with fighting infection are recruited to fight the cancer.

To test the effectiveness of the experimental therapy, Cui says investigators created mice with enormous tumors - the equivalent of one kilogram in humans - and injected them with the white cells.

"In other words, if they don't get cured, they will be dead," he said. "So, that kind of situation. So, we really sort of elevate[d] the level of challenge into a very high doses and also very advances stages of cancer."

Time and again, the therapy destroyed the cancer.

Bruce Beutler, a professor of immunology at Scripps Research Institute in California, notes that 98 percent of mouse genes are identical to human genes, so it's likely that a mighty mouse mutation against cancer exists in humans.

Berman: "So, what you really need to do is try to bottle it.

Beutler: "I suppose so. I think the key question now is what is the target and can the effect of the mutation be mimicked by a drug, is the second question."

But humans are not mice. Cui says there are many factors that go into cancer development in humans, including the fact the disease often occurs in old age and among young, healthy people. And sorting out the genetics will take some time.