GIST, gastrointestinal stromal tumor; IFS, infantile fibrosarcoma; IHC, immunohistochemistry; IMT, inflammatory myofibroblastic tumor; LPS, liposarcoma; MPS, massive parallel sequencing; NTRK, neurotrophic tyrosine receptor kinase; RT-PCR, reverse transcription polymerase chain reaction; TRK, tropomyosin receptor kinase.
a For patients at high risk of relapse, NTRK gene fusion testing might provide clinically actionable information for later in the disease course.
b If histology is typical then confirmation by MPS is recommended.
c Treatment may be considered concurrently with confirmatory MPS.
d Consider parallel validation by MPS or RT-PCR to confirm that fusion is in-frame.
e Avoid IHC screening in cases with myogenic and neural differentiation due to the high rate of false positivity.