Among the 3 tumors with weak-moderate expression of Pan-TRK, case #3 was diagnosed as NF1-related GIST, as described above, in which NTRK1 break-apart was captured in only a few tumor cells (<15%, Figure 4C) and could not be diagnosed as an NTRK1 rearrangement. The gene discussed is NTRK1; the disease is gastrointestinal stromal tumor.