Genetic testing, which is becoming more common for all cancer patients, could tell doctors which patients will benefit most from chemotherapy for acute myeloid leukemia.
By finding elusive blood stem cells and watching how they genetically express themselves, scientists have taken the first step toward a new way of finding the best of course of treatment for people with acute myeloid leukemia (AML).
Stem cells that form into blood cells sometimes undergo abnormal changes during a process known as methylation. Methylation is when tags called methyl groups attach themselves to genes in certain cells. These chemical changes in DNA also are known as epigenetic markers.
Researchers at Albert Einstein College of Medicine at Yeshiva University and Montefiore Medical Center in New York have discovered how these changes may influence the prognosis for people with AML. They hope a test can be developed based on their findings, which would let doctors know whether chemotherapy would be helpful or harmful for an AML patient.
阿米特博士时, an associate professor of medicine and developmental and molecular biology at Einstein and director of hematologic malignancies at Montefiore, specializes in analyzing the epigenetic markers on blood stem cells. He teamed up withDr. Ulrich Steidl, an associate professor of cell biology at Einstein and associate chair for translational research in oncology at Montefiore.
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Steidl told Healthline that without Verma’s lab, the work would not have been possible. Never before had a tiny sample of highly purified blood stem cells undergone an epigenetic, genome-wide analysis.
Researchers compared the “epigenetic signature” of healthy people’s blood stem cells to that of AML patients’ cancerous white blood cells. Those cancer patients with methylation patterns similar to those of the healthy control group lived twice as long.
The study,published this week inTheJournal of Clinical Investigation, looked at samples from 700 patients with AML. Steidl hopes clinical trials of their testing technique can begin in six months to one year, with results in as little as two years.
Leukemia is a cancer of the blood and bone marrow. AML is a particularly aggressive form of the disease that usually requires immediate treatment. Only 30 percent of AML cases can be cured.
Often, the first line of treatment—chemotherapy—does more harm than good. This happens in cases where the disease has already progressed to the point that patients would be better served by other treatments, such as a bone marrow transplant or an experimental treatment currently in clinical trials.
理查德·斯通博士, director of the Dana Farber Cancer Institute at Harvard, told Healthline that the Einstein research provides a “very important contribution” as a testing tool for AML patients, if it’s confirmed in clinical trials. He said it may also provide direction for researchers searching for new drug treatments for AML.
“We don’t have too many ‘hammers’ right now for this type of leukemia,” Stone said. “Every young person, virtually, gets chemotherapy first.”
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The new research highlights the way genetic testing is transforming cancer care. It is leading to improved outcomes for people with all types of cancer, not just leukemia.
Stone said that genetic mutations in tumor tissue offer all sorts of clues about what treatments to use and how patients will fare. “(Genetic testing) is taking off very rapidly,” he said. “For most cancers, it becomes sort of part of routine care.”
An online pollreleased this week by the Huntsman Cancer Institute at the University of Utah showed that 85 percent of Americans would turn to genetic testing if they were diagnosed with cancer. Almost three-fourths said they would be willing to provide their genetic information to scientists for research purposes.
Companies that perform genetic tests for cancer patients have appeared nationwide. Genetic tests can determine a person’s risk for cancer, pinpoint certain types of cancer, and lead to more effective therapies using so-called “designer drugs.”
The National Cancer Institute offers a
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Verma told Healthline that cancer is now understood to be a genetic disease. Mutations disrupt the function of a gene, which leads to development of the disease.
“Sometimes, a mutation in gene ABC means you will do bad, but a mutation in gene XYZ means you will do better,” he said. “New drugs are being developed that work only for selected [genetic] mutations.”
Steidl told Healthline that cancer is no longer categorized by organ—such as breast, colon, prostate, or lung. “If you look at the genes that are mutated, the molecular aberrations in these cancer cells are very, very different from patient to patient,” he said.
A dramatic response to a given therapy—or a lack of response—is determined by molecular parameters that scientists are just beginning to understand, Steidl said.
With emerging technology, the entire genome of a cancer cell can be quickly analyzed. Theoretically, this should fuel incredible advances in genetic research, if companies and governments are willing to pay, Steidl added.
“It’s like before we had a bicycle, and now we have a race car, but we don’t have money to pay for the gasoline,” he said. “The dilemma is that we’re in the best position possible to deliver progress for patients with cancer and other diseases.”