VOA慢速英语 新型基因治疗癌症法“精确”消灭目标（在线收听）

New Gene Therapy 'Precisely' Targets Cancer 新型基因治疗癌症法“精确”消灭目标

Cancer is one of the world’s most feared diseases, and with good reason: It’s the leading cause of death across the globe.

Every year, about 14 million people are diagnosed with cancer. That’s roughly the population of Los Angeles. Many are treated with powerful medicines, using chemotherapy. But the side effects can be as difficult as the disease. Others have surgery to combat the disease.

In the U.S., it is the leading cause of death for men and women aged 40- to 79-years-old, reports the American Cancer Society.

But a new therapy that works with an individual’s genes is on the horizon, says cancer expert William Nelson, M.D., Ph.D.

Nelson is director of the Kimmel Cancer Center at Johns Hopkins University in Baltimore, Maryland. It is ranked as one of America’s top cancer research facilities, according to the National Cancer Institute. 

“Precision medicine” is a new field of medicine that works with an individual’s “variations in genes, environment and lifestyle,” reports the National Institutes of Health (NIH). NIH is a federal research center for medicine in Bethesda, Maryland.

It is a fast-growing area of medicine. Nelson said almost every U.S. hospital and health care center is promoting precision medicine as a service.

In addition, President Obama launched a national “Precision Medicine Initiative” in January this year. The U.S. government funded it with $215 million. The White House said the program will speed up medical discoveries and give doctors “new tools, knowledge and therapies.” This will tailor treatments to the individual.               

Precision medicine can be a powerful tool in cancer treatment. Nelson explained that cancer happens when genes behave abnormally. A process called “gene sequencing” can make a map of all the cells in the body. Researchers can find genes that have mutated. Mutated genes cause cancer.

Technology speeds up the process of mapping genes. Nelson said, “The microprocessor power is doubling every 18 months.”

This is an important change from the way cancer drugs were developed before. In the past, Nelson said, cancer drugs were discovered by experiments in a lab. For example, scientists might discover a plant in the Amazon rain forest and test it in a lab to see if it could kill cancer cells.

But only 4 percent to 5 percent of cancer drugs discovered this way had any meaningful benefit. In 15 years of cancer research, only 1-in-20 or 1-in-30 drugs proved to be helpful, according to the cancer expert.

“We weren’t getting where we needed to go fast enough,” Nelson told the audience.

Plus, it was expensive. The pharmaceutical companies were spending an average of $1 billion to $2 billion to create a new drug, and a lot of these new drugs simply didn’t work, according to Nelson.

But then in the late 1990s, the discovery of gene sequencing changed all that. Pharmaceutical companies began creating new cancer drugs to stop the specific gene mutations found in different cancers.

For example, Herceptin was developed in 1998 to treat breast cancer.            

Gloevec was developed to treat leukemia. 

“We’re in a business where we have to know what the gene mutations are to defeat them,” said Nelson.

As a result, there has been an “accelerating pace of anti-cancer drugs, discovery, development and approval,” continued Nelson.

The Food and Drug Administration (FDA) approves all new drugs in the U.S. The FDA approved 12 anti-cancer drugs in 2013, 10 in 2014 and eight so far in 2015. Compare that to only two anti-cancer drugs that were approved by the FDA from 2008 to 2012.

Nelson said a new drug called nivolumab may recognize gene defects in each individual and unleash the immune system to attack the cancer.

“The gene test will ultimately save insurers money, because this will lead to a more efficient, targeted approach to cancer treatment,” concluded Nelson. 

Words in This Story

revolutionize – v. to change (something) very much or completely : to cause a revolution in (something)

makeup – n. the way in which something is put together or arranged 

innovations – n. the act or process of introducing new ideas, devices, or methods

chemotherapy – n.  the use of chemicals to treat or control a disease (such as cancer)

surgery – n. medical treatment in which a doctor cuts into someone's body in order to repair or remove damaged or diseased parts

tailored – v. to make (clothing that is measured to fit a particular person)

variations – n. a change in the form, position, condition, or amount of something

therapies – n. the treatment of physical or mental illnesses

mutated – v. to cause (a gene) to change and create an unusual characteristic in a plant or animal : to cause mutation in (a gene)

microprocessor – n.  the device in a computer that manages information and controls what the computer does

pharmaceutical – adj.  of or relating to the production and sale of drugs and medicine

accelerating – v.  to move faster : to gain speed

unleash – v. to allow or cause (something very powerful) to happen suddenly 

immune- adj.  of or relating to the body's immune system or protection from disease