Doctors have reported the first attempts in the US to use gene editing to help patients fight cancer.
One form of gene editing proved safe in three patients tested. However, it is not yet known what long-term effects the method will have on cancer treatment or patient survival rates.
The tests used a gene editing tool called CRISPR / Cas9, recently reported in a medical study. The method has been discovered in recent years as a means of altering a person's genome.
DNA is the abbreviation for deoxyribonucleic acid. It is the substance that carries genetic information in the cells of living things. The CRISPR tool makes it possible to modify the DNA to add or remove needed genes if this leads to problems.
Cancer researchers from the University of Pennsylvania Health System recorded immune system cells from the blood of three patients. They changed the structure of cell genes to recognize and fight cancer. They were then reinstated in the patients. The editing process was completed without serious side effects.
The treatment removed three genes that might limit the ability of the immune system cells to attack the cancer. A new, fourth gene has been added to assist the others in their effective work.
Two of the patients suffer from multiple myeloma, a blood cancer, and the third suffers from sarcoma, a cancer that forms in the connective tissue or soft tissue. All had failed with repeated traditional cancer therapies.
"It's the most complicated gene technology process ever tried," said study director Edward Walled City told The Associated Press (AP). "This is proof that we can genetically engineer these cells safely."
So far, the cells have survived and multiplied as they should, said City Wall.
After two to three months, one patient was diagnosed with cancer and the condition of another patient remained unchanged. The third patient was treated too early to measure her progress effectively. The researchers plan to extend the experimental treatment to 1
According to Stadtmauer, the treatment for gene editing is so new that it is not clear how quickly major effects against cancer can be expected. Patients continue to be monitored and more tests will be needed, he said.
"It's very early, but I'm incredibly encouraged," said an independent expert, Aaron Gerds, an AP reporter.
Gerds is a cancer specialist at the Cleveland Clinic in Cleveland, Ohio. He added that other cell therapies have worked very well on some blood cancers, even if they have "incurable diseases and cure them". He said that editing genes could provide a way to improve these treatments.
According to reports, Chinese scientists have tried the CRISPR method in cancer patients. The US study is the first known study to be completed outside of China. Researchers took more than two years to get approval from the US government.
More details about the study are due to be announced at the annual American Society of Hematology conference in December.
I am Bryan Lynn.
The Associated Press reported on this story. Bryan Lynn has adapted the report for VOA Learning English. George Grow was the publisher.
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edit words in this story
– n. Act of reform or reorganization
immune – adj. unable to be affected by a disease; Production of antibodies against diseases
complicated – adj. Include many different parts in a way that may be difficult to understand
Encourage – v. Trying to make someone more likely to do something