Fig. 4: Immunophenotype of gastrointestinal mesenchymal tumors with NTRK1 rearrangements.

TRK expression was diffused in all cases with variable intensity: cytoplasmic staining of strong intensity shown in case 7 (a) and moderately strong cytoplasmic staining in case 1 (b). CD34 (c) and S100 (d) were coexpressed in three tumors (case 6). SOX10 immunohistochemistry was consistently negative.