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Alexander Drilon, MD

Gregory J. Riely, MD, PhD


Frequency of NTRK Fusions in Gastrointestinal Stromal Tumors

By: Vanessa A. Carter, BS
Posted: Tuesday, July 26, 2022

Sang Joon Shin, MD, of Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Korea, and colleagues examined the TRK fusion status of patients with gastrointestinal stromal tumors who did not harbor KIT/platelet-derived growth factor receptor alpha (PDGFRA) mutations. Ultimately, these results, which were published in the journal Cancers, elucidated the molecular alterations surrounding KIT/PDGFRA wild-type gastrointestinal stromal tumors.

“Although KIT/PDGFRA wild-type gastrointestinal stromal tumors are rare, our clinical predictions could aid physicians in identifying patients eligible for NTRK fusion screening and therapeutic targeting,” suggested the investigators. “More effort should be devoted to improving methods to target this distinct disease subtype within the KIT/PDGFRA wild-type gastrointestinal stromal tumor group.”

The study authors retrospectively reviewed the data of 31 patients diagnosed with gastrointestinal stromal tumors who were negative for mutations of KIT/PDGFRA. Pan-TRK immunohistochemistry was performed to identify TRK expression in tumor samples, and fluorescence in situ hybridization was used to detect NTRK aberrations.

The median patient age at diagnosis was 56, and the median follow-up duration was 50 months. All patients underwent curative resection. A total of four patients died, three patients relapsed after treatment with surgery or imatinib, and one patient with recurrent disease received adjuvant therapy with imatinib. Among patients with no NTRK fusions, 53.8% had a primary tumor location of the stomach. In contrast, 20% of individuals who did harbor these rearrangements had tumors located in the stomach; 40% had tumors located in the small bowel and rectum.

A total of five individuals were found to demonstrate a weak-to-moderate TRK expression. Additionally, NTRK1 and NTRK3 fusions were observed in three and two tumor samples, respectively. The other 26 samples did not appear to harbor NTRK fusions; thus, the overall frequency of NTRK fusions in KIT/PDGFRA wild-type gastrointestinal stromal tumors was calculated to be 16%.

Disclosure: The study authors reported no conflicts of interest.

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