Tazemetostat was begun three months after completion of radiation therapy and administered at an oral dose of 1200 mg/m2/dose twice daily, the recommended phase II dose (RP2D) established in a pediatric phase I study of tazemetostat in rhabdoid tumors and INI1-negative tumors and used in Children’s Oncology Group NCI-COG Pediatric MATCH Consortium protocol APEC1621C for CNS-involved tumors12,15. The gene discussed is SMARCB1; the disease is rhabdoid tumor.