ALK and Histiocytosis: Importantly, the literature is replete with reports of exceptional responses of multiple tumor types bearing ALK fusions/rearrangements, both solid and hematologic, including but not limited to colorectal cancer, histiocytosis, leiomyosarcoma, lymphoma, multiple myeloma, neuroendocrine cancer, ovarian cancer, pancreatic cancer, renal cancer, thyroid cancer (even the aggressive anaplastic variant) after the patient was given an ALK inhibitor.