Interestingly, AS may also induce malignant transformation by the two p53 negative regulators MDM2 and MDM4 (MDMX), which are characterized by the existence of more than 70 splice variants for MDM2 (48) and 8 for MDM4 (49), some of which are tumor associated due to their ability to downregulate the tumor suppressor p53 more efficiently than other splice variants, underscoring again the relevance of AS for malignant transformation. The gene discussed is MDM4; the disease is neoplasm.