ALK and anaplastic large cell lymphoma: Similarly to ALK alterations in ALCL, NTRK alterations are specific to infantile fibrosarcoma, congenital mesoblastic nephroma, lipofibromatosis-like and inflammatory myofibroblastic tumor-like neoplasms, and secretory carcinomas of the breast and salivary glands and are potent molecular drivers of disease in these rare tumor entities.