Harvard Researchers Find Likely Tumor Cure

An international team of researchers led by Harvard Medical School Professor Bjorn R. Olsen has pinpointed a possible treatment for the most common tumor found in children.

The new research, published Oct. 19 in the journal Nature Medicine, claims to have found the mechanism by which the nonmalignant tumor grows and to have identified how to prevent the abnormal growth that causes infantile hemangioma.

As many as 10 percent of Caucasian infants—mostly girls—develop the benign tumor after birth. Made up of proliferating blood vessels, the tumor generally appears in the upper neck or head.

Though the tumor begins shrinking after several years and disappears by puberty, Olsen estimates that a tenth of patients with the tumor suffer side-effects ranging from obscured vision to physical disfigurement.

The study conducted by Olsen’s team observed tissue from nine infantile hemangioma patients at Harvard-affiliated Children’s Hospital and compared it to healthy tissue from boys’ foreskins.

The endothelial cells that line the blood vessels of the tumor, the study found, are derived from an abnormal cell not found in the healthy tissue. These cells have a self-replicating tendency that causes the proliferation of the tissue that creates the tumor.

The study found that a hormone called vascular endothelial growth factor (VEGF) activates the cells’ replication. Receptors on the outskirts of the endothelial cells normally bind with VEGF and restrict its activation. The team found that two gene mutations are likely responsible for missing receptors.

According to Olsen, anti-VEGF treatments already approved by the Food and Drug Administration for other conditions, including other cancers, could be used to prevent or limit the development of the infantile hemangioma tumor tissue.

For Olsen, the study is the culmination of over a decade’s worth of research.

In 1995, two post-doctoral fellows, Miikka Vikkula from Finland and Laurence Boon from Belgium, began research for Olsen on the abnormal formations of veins. By 2000, Vikkula and Boon had married and were running a vascular center in Brussels, but they stayed in contact with Olsen.

Teaming up with a group from Children’s Hospital, Olsen’s laboratory and the newlyweds set out to understand the mechanism of the infantile hemangioma tumor, and to eventually find a treatment.

Olsen said the research correlated with an industry-wide movement to perform research that can be used in practical situations, work known as “translational research” because the results of patient-based research are translated back to the patients.

“This paper is one example of what can be done with patient derived material,” Olsen said.

Olsen said that he still hopes to conduct clinical trials to confirm the benefits of anti-VEGF therapy in treating infantile hemangioma. But the team is also looking at other possible cures, including a way to induce pre-mature cell death in the endothelial cells. Another option would be to manipulate the mechanism by which the tumors naturally shrink, but that process is not yet understood.

“If we could speed that process up, then that would be another treatment, or maybe we could use a combination of [the treatments],” Olsen said. “That would be ideal.”

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