Stories about: leukemia

Do children with Down syndrome need modified chemo for leukemia? No, says study

leukemia down syndrome acute lymphoblastic leukemia

Clinicians have long known that children with Down syndrome carry an elevated risk of developing acute lymphoblastic leukemia (ALL), the most common pediatric cancer. Research consistently shows that children with Down syndrome are more likely to suffer complications from chemotherapy. At the same time, some studies have suggested that children with Down syndrome and ALL may have a higher chance of relapsing.

What to do with this knowledge has been a source of controversy. Should patients with ALL and Down syndrome receive treatment modified to minimize toxicity from chemotherapy? Or should they be given the same treatment as other children with ALL to minimize the chance for relapse? Recent study results from Dana-Farber/Boston Children’s Cancer and Blood Disorders Center suggest that full-dose chemo is preferable.

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Rainbow-hued blood stem cells shed new light on cancer, blood disorders

color-coded blood stem cells
These red blood cells bear color tags made from random combinations of red, green and blue fluorescent proteins. Same-color cells originate from the same blood stem cell (Nature Cell Biology 2016, Henninger et al).

A new color-coding tool is enabling scientists to better track live blood stem cells over time, a key part of understanding how blood disorders and cancers like leukemia arise, report researchers in Boston Children’s Hospital’s Stem Cell Research Program.

In Nature Cell Biology today, they describe the use of their tool in zebrafish to track blood stem cells the fish are born with, the clones (copies) these cells make of themselves and the types of specialized blood cells they give rise to (red cells, white cells and platelets). Leonard Zon, MD, director of the Stem Cell Research Program and a senior author on the paper, believes the tool has many implications for hematology and cancer medicine since zebrafish are surprisingly similar to humans genetically.

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Treating relapsed child leukemia by matching therapy to the mutations

next generation sequencing cancer drugs child leukemia
(Bainscou / National Cancer Institute / Wikimedia Commons)

Although current treatments can cure 80 to 90 percent of cases, acute lymphoblastic leukemia (ALL) remains the second leading cause of cancer deaths in children. Patients with a resistant form of the disease, who relapse following successful treatment or who have other high risk features have few treatment options. Acute myeloid leukemia (AML) is also difficult to treat in children.

In a first-of-its-kind study, investigators at the Dana-Farber/Boston Children’s Cancer and Blood Disorders Center are testing precision cancer medicine in children and young adults with relapsed or high-risk leukemias. The goal is to determine whether powerful next-generation DNA sequencing can spot mutations or genetic changes in leukemia cells that can be targeted by cancer drugs.

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Targeting leukemia with a clinical trial of CAR T-cell therapy

CAR T-cell immunotherapy relapsed leukemia targeted therapy

One of the immune system’s basic jobs is to tell “self” from “non-self.” Our cells carry markers that the immune system uses to recognize them as being part of us. Cells that don’t carry those markers—like bacteria and other pathogens—therefore don’t belong.

Cancer cells, however, fall into a gray area. They’re non-self, yet they also bear markers that connote self-ness—one of the reasons the immune system has a hard time “seeing” and reacting to cancer.

Can we focus the immune system’s spotlight on cancer cells? The provisional answer is yes. Research on cancer immunotherapy—treatments that spur an immune response against cancer cells—has boomed in recent years. (The journal Science recognized cancer immunotherapy as its Breakthrough of the Year in 2013.)

And one of the more recent methods—called chimeric antigen receptor (CAR) T-cell therapy—is now in a clinical trial for relapsed or treatment-resistant B-cell acute lymphoblastic leukemia (ALL) at the Dana-Farber/Boston Children’s Cancer and Blood Disorders Center.

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When is an antipsychotic not an antipsychotic? When it’s an antileukemic

A zebrafish model of leukemia has helped find that an antipsychotic drug has anticancer properties.One of the hot trends in drug discovery could be called drug re-discovery: finding new uses for drugs that have already received FDA approval for a different indication.

It’s an approach that allows researchers and clinicians to rapidly test potential treatments for rare or difficult-to-treat conditions. Because the drug’s safety profile is already known, much of the preclinical and early clinical work that goes into developing a drug can be bypassed.

It was this kind of strategy that Alejandro Gutierrez, MD, and A. Thomas Look, MD, of Dana-Farber/Boston Children’s Cancer and Blood Disorders Center, and Jon Aster, MD, PhD, of Dana-Farber Cancer Institute and Brigham and Women’s Hospital, had in mind when they started screening a library of nearly 5,000 FDA-approved compounds, off-patent drugs and natural products using a zebrafish model of T-cell acute lymphoblastic leukemia (T-ALL).

And with that strategy, they may have struck gold. Just not in the way they had expected.

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Customized cell therapy for untreatable diseases: Your tax dollars at work

Leonard Zon (top) and Massachusetts Lt. Governor Timothy Murray in the Stem Cell Program's zebrafish facility. (Courtesy MLSC)
Ed. Note: Leonard Zon, MD, is founder and director of the Boston Children’s Hospital Stem Cell Program, which yesterday was awarded $4 million by the Massachusetts Life Sciences Center to build the Children’s Center for Cell Therapy.

As a hematologist, I see all too many children battling blood disorders that are essentially untreatable. Babies with immune deficiencies living life in a virtual bubble, hospitalized again and again for infections their bodies can’t fight. Children disabled by strokes caused by sickle cell disease, or suffering through sickle cell crises that drug treatments can’t completely prevent. Children whose only recourse is to risk a bone marrow transplant—if a suitably matched donor can even be found.

Over the past 20 years, my lab and that of George Daley, MD, PhD, at Boston Children’s Hospital have worked hard to give these children a one-time, potentially curative option—a treatment that begins with patients’ own cells and doesn’t require finding a match.

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Leukemia talks to itself, or how AML cells can signal their own growth

We put lots of hurdles up to slow or stop cancer growth, but cancer cells often get over them. The more we know about the how they do it, though, the more we can do about it. (Phil Roeder/Wikimedia Commons)

Leukemia and other cancer cells are really good at hurdling over the obstacles we throw at them. It’s the whole basis of drug resistance: we attack a mutation with one drug, and another mutation arises to cancel out the drug’s effect. Or the cell ramps up other pathways to compensate for the one blocked by the drug.

But the more we learn about the backup systems cancer cells use to get around our treatment strategies, the better we can get at controlling or eliminating cancer cells. Alex Kentsis, MD, PhD, and Thomas Look, MD, of Dana-Farber/Children’s Hospital Cancer Center, came across one such backup while trying to find which genes a blood cancer called acute myeloid leukemia (AML) relies on to survive. In a nutshell: the cells talk to themselves—chemically, that is.

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Taking a targeted approach when leukemia comes back

Lewis Silverman, MD, thinks he may have a powerful new tool for treating children with relapsed acute lymphoblastic leukemia. (VashiDonsk/Wikimedia Commons)

The news that your child has cancer always comes as a shock, but for one cancer, acute lymphoblastic leukemia (ALL), parents can take comfort in the fact that doctors are really good at treating it. The cure rate for ALL has, over the last 40 years, climbed to nearly 90 percent.

Less comforting is the fact that some 10 to 20 percent of children who initially respond well to treatment suffer a relapse within five years. And right now, the drugs at our disposal aren’t very good at turning a relapse back into a remission.

“We have standard treatment regimens for newly diagnosed and relapsed ALL, both of which rely heavily on corticosteroids like prednisone and dexamethasone,” says Lewis Silverman, MD, director of the Pediatric Hematologic Malignancy Service at Dana-Farber/Children’s Hospital Cancer Center (DF/CHCC). “But we know that leukemias with any level of steroid resistance are more likely to relapse. Anything we can do to overcome that resistance would let us help many children.”

Silverman has launched a clinical trial that will try a new strategy for tearing down ALL cells’ barriers against corticosteroids.

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Whole-genome sequencing in medicine: New knowledge, new responsibilities

(Karl-Ludwig Poggemann/Wikimedia Commons)

Recently, in the hospital cafeteria, I overheard a group of researchers discussing the upcoming availability of whole-genome sequencing to physicians. “We should devise a way to study how physicians will use this,” said one of them—underscoring the disruptive nature of the transformation that is currently happening in medicine.

The ability to immediately obtain whole-genome sequences from patients holds enormous potential for understanding and treating human disease. The list of studies reporting successful diagnosis of otherwise elusive orphan conditions is already too long to recount—more than 600 articles in PubMed as of the date of this posting—including poignant examples of advancing clinical care.

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