Stories about: cancer

Angiogenesis: The slow growth of a science

angiogenesis

Sometimes a scientific idea takes a long time to make its way forward. Angiogenesis is a case in point. As surgeon-in-chief at Boston Children’s Hospital, Judah Folkman, MD, noted that malignant tumors often had a bloody appearance. In The New England Journal of Medicine in 1971, he hypothesized that tumors cannot grow beyond a certain size without a dedicated blood supply, and that “successful” tumors secrete an unknown substance that encourages blood vessel growth, or angiogenesis.

If angiogenesis could be blocked, he argued, tumors might not grow or spread. Rather than waging a toxic chemical and radiation battle with a tumor, one could starve it into submission by shutting down its blood supply.

The idea was roundly criticized.

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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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Pediatric brain tumor responding well to melanoma drug, targeting a shared mutation

low grade glioma dabrafenib

When Danny Powers showed gross motor delays and poor balance as a toddler, early intervention specialists told his mother, Christi, that the problem was likely weak muscle tone. But when Danny developed severe headaches at age 4 during a family vacation, Christi took him to a local emergency room, where a CT scan revealed a mass in his head. His eventual diagnosis back home in Massachusetts was low-grade glioma, the most common pediatric brain tumor.

Fortunately, low-grade gliomas are non-malignant, slow-growing and highly curable, and most children can look forward to decades of survival. Unfortunately, the standard treatment — chemotherapy and, in some cases, radiation, in addition to surgery — is toxic and can damage the developing brain and body. Moreover, the tumors often regrow, requiring retreatment. By the time Danny was 13, he had been treated twice with surgery and once with a year of chemotherapy, which Mark Kieran, MD, PhD, clinical director of the Brain Tumor Center at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center, likens to carpet bombing.

Instead of undergoing another course of chemotherapy when his tumor regrew yet again, Danny entered a clinical trial of a new, targeted drug that acts more like a guided missile — aimed directly at his cancer-causing mutation. 

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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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Give childhood cancer a place on the cancer ‘moonshot’

cancer moonshot

Cancer remains the leading disease-related cause of death in children in the United States. Yet, when it comes to cancer research funding and drug development, pediatric cancer is often left behind, writes David A. Williams, MD, president of Dana-Farber/Boston Children’s Cancer and Blood Disorders Center, in Boston Globe Media’s STAT.

Although there are more than 150 types of childhood cancer, pediatric cancer receives only a small fraction of NIH and National Cancer Institute funding, Williams writes. Yet, he points out, just as breakthroughs in adult cancer research can help children, breakthroughs in pediatric cancer can also benefit adults.

Williams and other members of the Coalition for Pediatric Medical Research recently met with the staff of Vice President Joseph Biden, leader of the federal government’s cancer moonshot. Their message? Make sure that pediatric cancer is represented on the moonshot.

Read Williams’s STAT piece.

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News Notes: Headlines in science and innovation

An occasional roundup of news items Vector finds noteworthy.

Zika’s surface in stunning detail; mosquito tactics

Zika virus
(Purdue University image/courtesy of Kuhn and Rossmann research groups)

We haven’t curbed the Zika epidemic yet. But cryo-electron microscopy — a newer, faster alternative to X-ray crystallography — at least reveals the structure of the virus, which has been linked to microcephaly (though not yet definitively). The anatomy of the virus’s projections gives clues to how the virus is able to attach to and infect cells, and could provide toeholds for developing antiviral treatments and vaccines. Read coverage in the Washington Post and see the full paper in Science.

Meanwhile, as The New York Times reports, scientists are coming together in an effort to control Zika by genetically manipulating the mosquito that spreads it, Aedes aegypti.

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Deconstructed ‘death receptors’ suggest new ways to tackle cancer, autoimmune disease

death receptors apoptosis cancer autoimmune
The 3-D structure of the Fas death receptor’s transmembrane region, consisting of three tightly packed helices shown here from three angles. Cancer-causing mutations deform this structure, preventing “time to die” signals from passing through. (Fu Q; et al. Molecular Cell, Feb. 5, 2016).

Programmed cell death, or apoptosis, helps keep us healthy by ensuring that excess or potentially dangerous cells self-destruct. One way cells know it’s time to die is through signals received by so-called death receptors that stud cells’ surfaces. When these signals go awry, the result can be cancer (uncontrolled cell growth) or autoimmune disease (cells self-destructing too readily).

Researchers at Harvard Medical School (HMS) and the Program in Cellular and Molecular Medicine at Boston Children’s Hospital deconstructed a death receptor called Fas to learn more about its workings, using nuclear magnetic resonance (NMR) spectroscopy to reveal its structure.

They found that for immune cells to hear the “time to die” signal, a portion of Fas called the transmembrane region must coil into an intricate three-part formation, allowing the signal to pass into the cell. The NMR imaging also revealed that the amino acid proline is critical for the formation’s stability. Cancer-causing mutations in the transmembrane region (one of them affecting proline itself) deformed this delicate structure and prevented signals from passing through.

This better understanding of the Fas death receptor, published last week in Molecular Cell, could lead to new approaches that bypass Fas to encourage apoptosis in cancer or, conversely, inhibit Fas in autoimmune disease.

Read more on HMS’s news site.

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Science seen: Oral cancer up close

oral squamous cell carcinoma oral cancer lymphatic system cancer metastasis

Oral squamous cell carcinoma (OSCC), a kind of oral cancer, affects some 30,000 Americans annually. It spreads through the lymphatic system and often has already metastasized by the time it’s diagnosed. The top image here, from a recent study in the American Journal of Pathology, is a healthy mouse tongue; the bottom is the swollen tongue of a mouse with OSCC. The cancerous tongue is overloaded with lymphatic vessels, appearing in blue and white, which help the tumor spread to the regional lymph nodes. The Bielenberg lab in Boston Children’s Hospital’s Vascular Biology Program is studying ways of blocking the progression of this and other cancers by inhibiting their spread through the lymphatic system. (Image: Bielenberg laboratory/Kristin Johnson)

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The cell that caused melanoma: Cancer’s surprise origins, caught in action

It’s long been a mystery why some of our cells can have mutations associated with cancer, yet are not truly cancerous. Now researchers have, for the first time, watched a cancer spread from a single cell in a live animal, and found a critical step that turns a merely cancer-prone cell into a malignant one.

Their work, published today in Science, offers up a new set of therapeutic targets and could even help revive a theory first floated in the 1950s known as “field cancerization.”

“We found that the beginning of cancer occurs after activation of an oncogene or loss of a tumor suppressor, and involves a change that takes a single cell back to a stem cell state,” says Charles Kaufman, MD, PhD, a postdoctoral fellow in the Zon Laboratory at Boston Children’s Hospital and the paper’s first author.

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