NTRK3 and fibrosarcoma: ETV6::NTRK3 fusion has been identified in not only infantile mesenchymal neoplasms, such as infantile fibrosarcoma/congenital “cellular” mesoblastic nephroma and secretory carcinomas of the breast, salivary gland, skin [34,35,36,37], but also in thyroid cancers associated with a history of radiation [38].