MIAMI (May 21, 2026) – Specific genetic fusion patterns in solitary fibrous tumors may help identify which patients face a higher risk of metastasis, recurrence and more aggressive disease behavior, according to new research that could improve how physicians assess and eventually treat this rare cancer. The study, led by researchers at Sylvester Comprehensive Cancer Center , part of the University of Miami Miller School of Medicine, will be presented in a rapid oral session at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting .
“This work is helping us move toward a more precision-based approach for these patients,” said Gina D’Amato, M.D. , sarcoma medical oncologist at Sylvester. “Instead of patients cycling through many different therapies, our goal is to better understand which tumors are more aggressive and which treatments may work best based on the biology of the disease.”
Solitary fibrous tumor (SFT) is a subtype of sarcoma, which is a cancer that develops in connective tissues such as fat, muscle, blood vessels and fibrous tissue. SFTs most commonly develop in the chest cavity but can also occur in the abdomen, pelvis, brain and extremities.
The study was led by Andrew Rosenberg, M.D. , a Sylvester researcher, clinical professor in the Miller School’s Division of Pathology and Laboratory Medicine and co-chief of anatomic pathology. It was conducted as part of The Horowitz Solitary Fibrous Tumor Initiative at Sylvester , which was founded with philanthropic support from patient advocate Joel Horowitz. The initiative supports research, patient registries and molecular profiling efforts focused on SFT.
“Research on rare tumors requires a large collaborative team,” D’Amato said. “Sylvester’s internal infrastructure, core facilities, tissue banking and molecular profiling capabilities have allowed us to build this kind of rare tumor research program.”
Physicians currently use a clinical risk scoring system called the Demicco score to estimate how aggressively an SFT may behave. The score considers factors such as patient age, tumor size and how the tumor appears under a microscope. The new study explored whether genetic information could add another layer of precision to understanding this cancer.
“With more common cancers, we already know certain mutations can help predict prognosis or response to therapy,” said Keerthana Sureshkumar, first author of the study and a medical student at the Miller School. “For solitary fibrous tumors, we are still trying to build that knowledge base.”
SFTs are defined by a genetic fusion called NAB2-STAT6, which happens when two neighboring genes on chromosome 12 break apart and fuse back together at the wrong spot.
The study analyzed 48 SFT patients treated at Sylvester. Researchers reviewed patient charts, clinical outcomes and molecular profiling reports to see whether the NAB2-STAT6 fusion breakpoint correlated with how the cancer behaved.
Researchers categorized tumors by where the fusion occurred. There are multiple known variants, which the researchers found could be split into proximal and distal groups. Breakpoints closer to the beginning of the genes are proximal breakpoints. Distal breakpoints occurred farther downstream.
They found that patients with distal variants were more likely to develop cancer that spread. None of the patients with proximal variants had cancer that spread from the original tumor, compared with a quarter of patients with distal variants.
“This was one of the most striking findings,” Sureshkumar said. “Despite the relatively small sample size, we saw very strong signals that these molecular differences may carry important information about the patients’ prognosis.”
“The study suggests that fusion variants are potential biomarkers,” D’Amato said. “The hope is that these tools could eventually become both predictive and prognostic, helping us better understand which patients may need more aggressive treatment or closer monitoring.”
“The data are still preliminary, so this is too soon to directly guide treatment recommendations,” she said. “Right now, this is more of a sign that we are heading in the right direction.”
The researchers don’t know yet why or how the breakpoint causes more aggressive disease. They are now focused on developing cell and preclinical models to better study the variants and understand which treatments work best.
“We have developed and are expanding the SFT registry internationally so we can study a much wider group of patients,” D’Amato said. “That allows us to connect molecular findings with clinical outcomes and better understand how these tumors behave over time.”
Read more about Sylvester’s efforts to advance cancer research through big data on the InventUM blog and follow @SylvesterCancer on X for the latest news on its research and care.
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Meeting: ASCO 2026 Annual Meeting
Poster Title: Association of NAB2-STAT6 distal fusion with risk level of metastatic disease and thoracic primary site.
Date/Time: May 31, 2026, 5:36-5:42 CDT
Location: S504; Live Stream