MDM2 and neoplasm: On the other hand, SIVA has been reported to suppress p53 activity by stabilizing the interaction between MDM2 and p53, leading to increased p53 ubiquitination and degradation, and increased bromodeoxyuridine (BrdUrd) incorporation [19,49], indicating that SIVA could also play a tumor-promoting role, further validating that the role of SIVA varies with cellular context.