A Rare <i>TP53</i> Mutation Predominant in Ashkenazi Jews Confers Risk of Multiple Cancers.

Abstract

Germline mutations in <i>TP53</i> cause a rare high penetrance cancer syndrome, Li-Fraumeni syndrome (LFS). Here, we identified a rare <i>TP53</i> tetramerization domain missense mutation, c.1000G>C;p.G334R, in a family with multiple late-onset LFS-spectrum cancers. Twenty additional c.1000G>C probands and one c.1000G>A proband were identified, and available tumors showed biallelic somatic inactivation of <i>TP53</i>. The majority of families were of Ashkenazi Jewish descent, and the <i>TP53</i> c.1000G>C allele was found on a commonly inherited chromosome 17p13.1 haplotype. Transient transfection of the p.G334R allele conferred a mild defect in colony suppression assays. Lymphoblastoid cell lines from the index family in comparison with <i>TP53</i> normal lines showed that although classical p53 target gene activation was maintained, a subset of p53 target genes (including <i>PCLO, PLTP, PLXNB3</i>, and <i>LCN15</i>) showed defective transactivation when treated with Nutlin-3a. Structural analysis demonstrated thermal instability of the G334R-mutant tetramer, and the G334R-mutant protein showed increased preponderance of mutant conformation. Clinical case review in comparison with classic LFS cohorts demonstrated similar rates of pediatric adrenocortical tumors and other LFS component cancers, but the latter at significantly later ages of onset. Our data show that <i>TP53</i> c.1000G>C;p.G334R is found predominantly in Ashkenazi Jewish individuals, causes a mild defect in p53 function, and leads to low penetrance LFS. SIGNIFICANCE: <i>TP53</i> c.1000C>G;p.G334R is a pathogenic, Ashkenazi Jewish-predominant mutation associated with a familial multiple cancer syndrome in which carriers should undergo screening and preventive measures to reduce cancer risk.