The dual inactivation of SMARCA4/BRG1 and SMARCA2/BRM genes of the ATPases in SWI/SNF chromatin remodeling complexes not only creates an epigenetic dysregulation and an increase in the lethality of the tumor effects, it also induces dedifferentiation of a normal to low grade tumor into a tumor with or without rhabdoid features that is graded as highly aggressive. This evidence concerns the gene SMARCA4 and neoplasm.