It has been hypothesized that the dual deficiency in key members of the SWI/SNF complex (e.g., SMARCA4 and SMARCA2, or SMARCB1 and SMARCA2) can induce dedifferentiation from a normal cell or a low-grade tumor into an aggressive high-grade tumor with small cell and/or rhabdoid features [17]. The gene discussed is SMARCA4; the disease is neoplasm.