MDM4 and tongue squamous cell carcinoma: Consistent with this, the most affected family member, with a lymphocyte telomere length within or below the first percentile of age-matched participants and a tongue squamous cell carcinoma at age 27, exhibited a WT MDM4 allele with three single-nucleotide polymorphisms (SNPs) associated with increased p53 activity in addition to the MDM4T454M allele.