NTRK3 and congenital fibrosarcoma: The ETS variant gene 6-neurotrophin receptor 3 (ETV6-NTRK3) gene fusion product identified by RT-PCR is diagnostic for infantile fibrosarcoma and the ETV6-NTRK3 transcript was present in 87.2% of patients in the investigation performed by the European Pediatric Soft Tissue Sarcoma Study Group [15].