Paediatric adrenocortical carcinoma is a rare malignancy with poor prognosis. Here we analyse 37 adrenocortical tumours (ACTs) by whole-genome, whole-exome and/or transcriptome sequencing. Most cases (91%) show loss of heterozygosity (LOH) of chromosome 11p, with uniform selection against the maternal chromosome. IGF2 on chromosome 11p is overexpressed in 100% of the tumours. TP53 mutations and chromosome 17 LOH with selection against wild-type TP53 are observed in 28 ACTs (76%). Chromosomes 11p and 17 undergo copy-neutral LOH early during tumorigenesis, suggesting tumour-driver events. Additional genetic alterations include recurrent somatic mutations in ATRX and CTNNB1 and integration of human herpesvirus-6 in chromosome 11p. A dismal outcome is predicted by concomitant TP53 and ATRX mutations and associated genomic abnormalities, including massive structural variations and frequent background mutations. Collectively, these findings demonstrate the nature, timing and potential prognostic significance of key genetic alterations in paediatric ACT and outline a hypothetical model of paediatric adrenocortical tumorigenesis.
Bibliographical noteFunding Information:
We thank the St Jude Children’s Research Hospital Hartwell Center, Tissue Resources Core Facility, Marc Valentine and the Cytogenetics Laboratory, and Pathology Department for expert assistance and Drs Charles Mullighan, Kathryn Roberts and Evan Parganas for assistance with figures. We thank Drs Gad B. Kletter, Andres Yunes and Ana Luisa Seidinger for clinical samples. We thank Sharon Naron for scientific edition. This work was supported by Cancer Center Support grant CA21765 and grants EY014867, EY018599 and CA168875 (M.A.D.) from the National Institutes of Health and by the American Lebanese Syrian Associated Charities (ALSAC). Whole-genome sequencing was supported as part of the St Jude Children’s Research Hospital– Washington University Pediatric Cancer Genome Project. M.A.D. is a Howard Hughes Medical Institute Investigator.