Identifying patients with NTRK fusion cancer

Ann Oncol. 2019 Nov:30 Suppl 8:viii16-viii22. doi: 10.1093/annonc/mdz384. Epub 2019 Dec 24.


Due to the efficacy of tropomyosin receptor kinase (TRK) inhibitor therapy and the recent Food and Drug Administration approval of larotrectinib, it is now clinically important to accurately and efficiently identify patients with neurotrophic TRK (NTRK) fusion-driven cancer. These oncogenic fusions occur when the kinase domain of NTRK1, NTRK2 or NTRK3 fuse with any of a number of N-terminal partners. NTRK fusions are characteristic of a few rare types of cancer, such as secretory carcinoma of the breast or salivary gland and infantile fibrosarcoma, but they are also infrequently seen in some common cancers, such as melanoma, glioma and carcinomas of the thyroid, lung and colon. There are multiple methods for identifying NTRK fusions, including pan-TRK immunohistochemistry, fluorescence in situ hybridisation and sequencing methods, and the advantages and drawbacks of each are reviewed here. While testing algorithms will obviously depend on availability of various testing modalities and economic considerations for each individual laboratory, we propose triaging specimens based on histology and other molecular findings to most efficiently identify tumours harbouring these treatable oncogenic fusions.

Keywords: NTRK fusions; ancillary testing; next-generation sequencing; tyrosine kinase inhibitor.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Biomarkers, Tumor / genetics
  • Biomarkers, Tumor / metabolism
  • High-Throughput Nucleotide Sequencing / methods
  • Humans
  • Immunohistochemistry / methods
  • In Situ Hybridization, Fluorescence / methods
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / metabolism
  • Neoplasms / diagnosis
  • Neoplasms / genetics*
  • Neoplasms / metabolism*
  • Oncogene Proteins, Fusion / genetics*
  • Oncogene Proteins, Fusion / metabolism*
  • Receptor, trkA / genetics*
  • Receptor, trkA / metabolism*
  • Receptor, trkB / genetics
  • Receptor, trkB / metabolism
  • Receptor, trkC / genetics
  • Receptor, trkC / metabolism


  • Biomarkers, Tumor
  • Membrane Glycoproteins
  • NTRK1 protein, human
  • NTRK3 protein, human
  • Oncogene Proteins, Fusion
  • Receptor, trkA
  • Receptor, trkB
  • Receptor, trkC
  • tropomyosin-related kinase-B, human