BCOR and endometrioid stromal sarcoma: Fusion transcripts involving the BCOR gene have also been described in a diversity of tumors extrinsic to the CNS including clear cell sarcoma of the kidney [37, 48], ossifying fibromyxoid tumors [21], acute promyelocytic leukemia [50], endometrial stromal sarcoma (ESS) [27, 31], adult non-uterine sarcoma [51], and a subset of small blue round cell sarcomas [34, 35, 41].