MDM4 and neoplasm: On the other hand, the SNPs rs10900598, rs1380576 and rs11801299 in the MDM4 gene, which encodes a protein that acts as a negative regulator of p53, were significantly associated with HPV16+ SCCOP and when combined all risk genotypes of the three polymorphisms, the patients carrying 1–3 MDM4 risk genotypes were approximately 2.5 times as likely to have an HPV16-positive tumor than those with no risk genotypes [91].