Immunohistochemistry for BCOR (Fig. 1B) and MYOD1 (Fig. 1C) were positive in the two cases classified as BCOR-rearranged sarcoma and MYOD1-mutant RMS, respectively (#11 and #12), thus corroborating the diagnoses suggested by DNAm profiling. The gene discussed is BCOR; the disease is sarcoma.