DDX3X suppresses neural lineage susceptibility to medulloblastoma [DNA-Seq]

DDX3X is frequently mutated in the WNT and SHH subtypes of medulloblastoma Ð the commonest malignant childhood brain tumor. But whether DDX3X functions as a medulloblastoma oncogene or tumor suppressor gene is not known. Here we show that Ddx3x regulates hindbrain patterning and development by controlling Hox gene expression and cell stress signaling. In mice predisposed to Wnt or Shh-medulloblastoma Ddx3x sensed oncogenic stress and suppressed tumor formation. WNT and SHH-medulloblastomas normally arise only in the lower and upper rhombic lips respectively. Deletion of Ddx3x relived this lineage restriction enabling both medulloblastoma subtypes to arise in either germinal zone. Thus DDX3X is a medulloblastoma tumor suppressor that regulates hindbrain development and restricts the competence of cell lineages to form medulloblastoma subtypes. Overall design: DNA-sequencing profiles of tumors formed from aberrant Wnt or Shh signalling. At least 3 replicates per genotype. The 2 Normal samples represent tumors caused by aberrant wnt or shh signalling but DO NOT have loss of ddx3x in any form.