This is the VOA Special English Health Report.

A new study demonstrates what researchers say is the first successful use of genetic engineering to treat cancer.  The researchers say they were able to get normal cells from a person's own defense system to recognize and attack cancer cells. 

The study involved patients with advanced melanoma, the deadliest form of skin cancer.  Steven Rosenberg led the study team at America’s National Cancer Institute.  The treatment was not able to save fifteen of the seventeen patients in the study.  But the researchers say the other two are disease-free eighteen months after the therapy began.  And they say it might be possible to use this method to treat other cancers.  The results appear in Science magazine. 

Now, here is more information about our story last week on a study by scientists at Advanced Cell Technology.  They said they produced embryonic stem cells using what the company called "an approach that does not harm embryos." 

The company said its method makes stem cells from a single cell taken from an eight-cell human embryo.  In fact, as critics noted, all sixteen embryos used in the experiment were destroyed as the scientists removed ninety-one cells in all.  The scientists said they developed stem cell lines from two of these cells. 

Many experts see the use of embryonic stem cells as a possible way to treat diseases.  Critics of the study included an official of the United States Conference of Catholic Bishops.  He said the experiment "left no embryos alive, and solves no ethical problem."

Company chief William Caldwell dismissed such criticism.  He says the aim was to develop a way to make embryonic stem cell lines that would not require the destruction of an embryo. 

The Wall Street Journal newspaper reported Tuesday that some researchers have questions about the experiment.  They say they want more evidence to show how a single cell can be used to create a stem cell line.

Nature magazine released the study online on August twenty-third.  Nature had to correct its own press release about the experiment two times.

Advanced Cell Technology became an independent company early last year.  It does not sell any products yet.  Two days after its report appeared, the company announced two financing deals with existing investors.  These deals could bring more than thirteen million dollars to the company.

And that's the VOA Special English Health Report.  I'm Steve Ember.