Adrenocortical tumors (ACT) are very rare, affecting only 3-4 out of every 10 million people per year younger than 15 years. However, the incidence of ACT varies worldwide from 0.1 per million per year in Hong Kong to 3.4 per million per year in southern Brazil, where a cluster of ACT has been discovered (Ribeiro and Gigueriredo 2004). The United States Surveillance, Epidemiology, and End Results (SEER) database estimates that there are about 25-30 new ACT cases per year in children and adolescents (Altekruse SF 2010). Adrenocortical tumors account for 0.2% to 0.4% of all childhood cancers. The median age of children with ACT is 3.2 years. About 65% of patients with ACT are younger than 5 years. Fewer than 15% of patients are 13 years or older at the time of diagnosis. The incidence of ACT is higher among girls. The pediatric ACT age distribution resembles that of tumors of embryonic origin. ACT can also occur in adults, typically in adults in their 40s and 50s. The clinical manifestations and outcomes of adult ACT differ from those in the pediatric age group. These observations suggest that the pathogenesis of ACT in children differs from that in adults.
Pediatric ACT is frequently associated with TP53 mutations (Varley, McGown et al. 1999; Ribeiro, Pinto et al. 2011). These mutations are usually inherited from one parent. In a small proportion of ACT cases, the mutation occurs for the first time in the child with ACT. Occasionally, TP53 mutations are restricted to tumor cells.
Researchers at St. Jude Children’s Research Hospital have conducted epidemiologic and laboratory research projects on ACT in children and adolescents. Specifically, they are investigating the role of the TP53 gene and its pathways on ACT development (West, Ribeiro et al. 2006; Russel-Swetek, West et al, 2008; Pinto, Ribeiro et al. 2011). They are also investigating the success or failure of new drugs by using ACT cells growing in cultures (in vitro) or in mouse models. Finally, a large number of children with ACT and their families have been studied to determine the natural history of ACT and development of other cancers. St. Jude currently participates in collaboration with investigators of the Children’s Oncology Group on an international treatment protocol whose aims are to investigate a modified surgical approach and examine the role of adjuvant chemotherapy.