[by:www.tingvoa.com - VOA英语网]
[00:00.10]Liver cancer is the sixth most common cancer in the world,
[00:05.61]and now researchers are developing new forms of treatment.
[00:12.71]If tests show you have liver cancer, there are several ways to treat the disease.
[00:19.45]One is removing the cancerous part of the liver.
[00:24.26]The other is having doctors replace the organ through a transplant operation.
[00:32.41]Patients who get someone else's liver must take immuno-suppressant drugs the rest of their life.
[00:41.19]The drugs keep the body from rejecting the new organ.
[00:46.91]There may be serious side effects that come with taking those powerful medicines.
[00:53.81]Chemotherapy and radiation treatments are also used to treat liver and other cancers.
[01:02.06]Those treatments require the patient to take strong drugs or exposure to radiation.
[01:11.08]The drugs or radiation destroy the cancer cells.
[01:17.00]But then, the healthy cells around the tumor are damaged.
[01:22.98]Now scientists are working on an experimental, minimally invasive treatment.
[01:31.47]They say it reduces the chances of harming the patient.
[01:37.38]This treatment involves the use of natural, non-poisonous chemicals from plants.
[01:46.06]That is why the researchers call it a “green” method for fighting cancer.
[01:53.28]Kattesh Katti is a professor of radiology and physics at the University of Missouri's School of Medicine.
[02:04.24]For more than 10 years, he has studied the use of nanotechnology to fight cancer.
[02:12.10]Nanotechnology is the science of making things unimaginably small.
[02:20.67]For this study, Katti used extremely small objects to target
[02:28.04]and destroy precancerous tumor cells in the livers of mice and human cells in the laboratory.
[02:38.89]“It sounds like a fairy tale, but we are really in advanced stages
[02:43.73] in terms of tumor treatment, in terms of disease diagnostics."
[02:49.74]Kattesh Katti used very small particles of gold.
[02:55.15]The gold was covered in a protective material called gum arabic.
[03:02.90]It comes from an acacia tree.
[03:06.66]He says the particles attract precancerous and cancer cells.
[03:13.78]Those cells are far more affected by lower levels of heat than healthy cells.
[03:22.52]Once the particles travel to and connect with the cells, they are heated with a laser.
[03:31.46]That destroys the cancer cells, but the healthy ones around them live.
[03:39.69]Katti explains how the treatment would work on a human patient.
[03:46.88]“The patient will be administered with these nano particles.
[03:50.32]Within a couple of hours,
[03:52.22]the patient will be treated with lasers, and then the patient can go home.
[03:56.71]So, there is no radioactivity.
[03:58.53]There is no toxic waste.
[04:00.50]There is no toxicity, systemic toxicity, to the patient.”
[04:04.58]What that means is the patient would not have the same side effects
[04:11.08]one can have from radiation and chemotherapy.
[04:16.07]Chemotherapy drugs often are toxic.
[04:20.99]While they kill off the cancer tumors,
[04:25.11] they are also poisonous to the healthy cells and the patient can get very sick.
[04:31.71]Katti says the cost of treatment will be low because one gram of gold can be used to treat 50 patients.
[04:44.12]He says this form of treatment could be used for other types of cancer, arthritis and other diseases.
[04:54.70]The next step is testing in human subjects.
[04:59.93]If this treatment method works, it will be good news for the nearly 800,000 people
[05:08.49]who are found to have liver cancer every year.
[05:12.94]It may also help save the lives of some 700,000 people who die every year from the disease.
[05:23.84]More than 80 percent of the liver cancer cases are found in less developed countries,
[05:33.36]with the highest numbers in Asia and Africa.
[05:37.75]In the United States, liver cancer is one of the top 10 cancers that kill.
[05:45.86]I'm Anne Ball.