NTRK Fusion

An NTRK fusion is a rare genetic abnormality in which one of the NTRK genes (NTRK1, NTRK2, or NTRK3) becomes fused to another gene, producing an abnormal protein that drives cancer cell growth. When present in a tumor, this fusion can often be targeted with specific drugs called TRK inhibitors. NTRK fusions are uncommon in mesothelioma but, when found, can open the door to targeted therapy.

Origin

NTRK stands for Neurotrophic Tyrosine Receptor Kinase, a family of genes first characterized in the 1980s for their role in nervous system development. Their importance as cancer drivers became widely recognized in the 2010s, leading the FDA to approve the first tumor-agnostic TRK inhibitor, larotrectinib, in 2018.

Significance in Asbestos Context

For a patient with mesothelioma, NTRK fusion testing is one of several molecular tests that may reveal a treatable target beyond standard chemotherapy and immunotherapy. Although NTRK fusions occur in only a small percentage of mesothelioma cases, the impact when found is significant. FDA-approved TRK inhibitors such as larotrectinib (Vitrakvi) and entrectinib (Rozlytrek) can produce durable responses regardless of where the cancer originated. Patients should ask their oncologist whether their tumor has undergone comprehensive genomic profiling (often via next-generation sequencing) that includes NTRK1, NTRK2, and NTRK3, especially if standard treatments are failing or if they are considering a clinical trial. The presence or absence of such testing in the medical record may also matter to a legal claim, since documented molecular features support the diagnosis and inform prognosis and damages.

Example Sentence

After her pleural mesothelioma progressed on first-line chemotherapy, her oncologist ordered next-generation sequencing, which identified an NTRK fusion and made her eligible for treatment with a TRK inhibitor.

Related Terms

Next-Generation Sequencing, Targeted Therapy, BAP1, Molecular Profiling, Tumor-Agnostic Therapy, Mesothelioma

Notes

• Ask your oncologist whether your tumor has been tested with a comprehensive next-generation sequencing panel that specifically includes NTRK1, NTRK2, and NTRK3 fusions.
• If an NTRK fusion is found, ask about FDA-approved TRK inhibitors (larotrectinib, entrectinib) and whether a clinical trial would be appropriate.
• Request that any molecular pathology reports be added to your medical records and keep your own copies. These reports are important for treatment decisions, second opinions, and any legal claim.
• Because NTRK fusions are rare in mesothelioma, consider seeking a second opinion or evaluation at a mesothelioma specialty center where molecular testing is routine.