Researchers identify first drug targets in childhood genetic tumor disorder

Two mutations central to the development of infantile myofibromatosis (IM)—a disorder characterized by multiple tumors involving the skin, bone, and soft tissue—may provide new therapeutic targets, according to researchers from the Icahn School of Medicine at Mount Sinai.

The findings, published in the American Journal of Human Genetics, may lead to new treatment options for this debilitating disease, for which the only current treatment option is repeated surgical removal of the tumors.

IM is an inheritied disorder that develops in infancy or even in utero and tumors continue to present throughout life. The tumors do not metastasize, but can grow large enough to invade the tissue surrounding them causing physical limitations, disfiguration, bone destruction, intestitinal obstruction, and even death. Currently, the standard of care is to excise the tumors when possible, which can be invasive, painful, and disfiguring, and most patients require multiple surgeries throughout their lives.

Led by John Martignetti, MD, PhD, Associate Professor of Genetics and Genomic Sciences, Oncological Sciences, and Pediatrics and other researchers at the Icahn School of Medicine at Mount Sinai and Hakon Hakonarson, MD, PhD at the Children's Hospital of Philadelphia, the global research team gathered blood samples from 32 people from nine different families affected by the disease and performed whole-exome sequencing, a type of genomic sequencing where all protein coding regions of the genome, called the exome, are analyzed. They identified mutations in two genes: PDGFRB and NOTCH3.

“We are very excited about the findings of this study, which started 10 years ago with the enrollment of the first family,” said Dr. Martignetti. “The newest developments in sequencing technology have led to a new breakthrough in understanding this debilitating disease and we can therefore begin identifying drug-based treatments to save lives for some and avoiding the negative quality of life impact of extensive and repeated surgery in others.”

PDGFRB and NOTCH3 are two genes that are targeted by existing drugs, including imatinib (GLEEVEC®) and sunitinib (Sutent®). Next, Dr. Martignetti and his team plans to test whether cells grown in the laboratory from myfibromatosis tumors are susceptible to these drugs. They also hope to learn why mutations in these two genes result in disease.

“If we can learn how these mutated genes get hijacked to cause cellular miscommunication, and also test existing and novel therapies to see if they shrink the tumors, we hope to improve the lives of the individuals battling this disease,” said Dr. Martignetti.

About The Mount Sinai Medical Center

The Mount Sinai Medical Center encompasses both The Mount Sinai Hospital and Icahn School of Medicine at Mount Sinai. Established in 1968, the Icahn School of Medicine at Mount Sinai is one of the leading medical schools in the United States. The Icahn School of Medicine is noted for innovation in education, biomedical research, clinical care delivery, and local and global community service. It has more than 3,400 faculty members in 32 departments and 14 research institutes, and ranks among the top 20 medical schools both in National Institutes of Health (NIH) funding and by U.S. News & World Report.

The Mount Sinai Hospital, founded in 1852, is a 1,171-bed tertiary- and quaternary-care teaching facility and one of the nation's oldest, largest and most-respected voluntary hospitals. In 2012, U.S. News & World Report ranked The Mount Sinai Hospital 14th on its elite Honor Roll of the nation's top hospitals based on reputation, safety, and other patient-care factors. Mount Sinai is one of just 12 integrated academic medical centers whose medical school ranks among the top 20 in NIH funding and by U.S. News & World Report and whose hospital is on the U.S. News & World Report Honor Roll. Nearly 60,000 people were treated at Mount Sinai as inpatients last year, and approximately 560,000 outpatient visits took place.

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