Module 2
Testing for NTRK gene fusions allows for the identification of patients who may benefit from TRK inhibitor therapy. Information on NTRK gene fusions testing is reviewed over the following pages, and the recommended NTRK gene fusions testing algorithm can be found here. In order to accurately identify patients who may benefit from TRK- targeted therapies, NTRK fusion testing needs to be done consistently and with sensitive and specific methodologies.
Techniques routinely used to detect NTRK gene fusions include DNAgenomic-based approaches [DNA or RNA next-generation sequencing (NGS), RNA-based NGS, reverse-transcriptase PCR (RT-PCR), )], and histology-based approaches [fluorescence in situ hybridisation (FISH), and immunohistochemistry (IHC).)]. Each technique detects the NTRK gene fusions either at the DNA, RNA, or protein level (see below). Novel techniques using liquid biopsy or Nanostring technology are being investigated and are likely to be introduced into the clinical practice in the coming years.