TP53 and neoplasm: Given the frequency of other TP53 germline mutations in other countries of between 1:5000 and 1:20,000 births [12,40] and 80% frequency of low-penetrance germline TP53 mutations identified in pediatric ACT as reported by the Manchester Children’s Tumor Registry [6], it is important to consider the influence of environmental factors on the development of ACT in R337H carriers.