The incidence of pediatric adrenal cortical carcinoma (ACC) in southern Brazil is 10–15 times higher than that of pediatric ACC worldwide. Because childhood ACC is associated with Li-Fraumeni syndrome, we examined the cancer history and p53 status of 36 Brazilian patients and their families. Remarkably, 35 of 36 patients had an identical germ-line point mutation of p53 encoding an R337H amino acid substitution. Differences within intragenic polymorphic markers demonstrated that at least some mutant alleles arose independently, thus eliminating a founder effect. In tumor cells, the wild-type allele was deleted, and mutant p53 protein accumulated within the nuclei. Although these features are consistent with Li-Fraumeni syndrome-associated adrenal tumors, there was no history of increased cancer incidence among family members. Therefore, this inherited R337H p53 mutation represents a low-penetrance p53 allele that contributes in a tissue-specific manner to the development of pediatric ACC.

Purpose: We created a registry for pediatric adrenocortical tumors (ACTs), which are rare and are not well characterized. We provide a descriptive analysis of 254 patients registered on the International Pediatric Adrenocortical Tumor Registry. Patients and Methods: Between January 1990 and December 2001, 254 patients younger than 20 years of age with newly diagnosed or previously treated ACTs were registered. A histologic diagnosis of ACT was required, although central review was not mandatory. Follow-up information was periodically requested from the referring physician. Treatment was chosen by the primary physician. Results: The overall female-male ratio was 1.6:1, but it varied widely among age groups. The most common presenting sign (84.2%) was virilization. Cushing's syndrome without virilization was uncommon (5.5%). Tumors were completely resected in 83% of patients. Patients with disseminated or residual disease received mitotane, cisplatin, etoposide, and/or doxorubicin, and rarely, radiation therapy. At a median follow-up of 2 years and 5 months, 157 patients (61.8%) survived without evidence of disease and 97 patients (38.2%) had died. The 5-year event-free survival estimate was 54.2% (95% CI, 48.2% to 60.2%). In a multivariate analysis, disease stage, presenting signs of endocrine dysfunction, and age were independently associated with prognosis. Conclusion: Childhood ACTs occur predominantly in females and almost always causes clinical signs. Complete resection is required for cure. Residual or metastatic disease carries a poor prognosis. Our results demonstrate the feasibility of a disease-specific database for obtaining meaningful clinical and outcome information.

Purpose: The incidence of pediatric adrenocortical tumors (ACTs) is remarkably high in southern Brazil, where more than 90% of patients carry the germline TP53 mutation R337H. We assessed the impact of early detection of this mutation and of surveillance of carriers. Patients and Methods: Free newborn screening was offered at all hospitals in the state of Paraná. Parents of positive newborns were tested, and relatives in the carrier line were offered screening. Positive newborns and their relatives age < 15 years were offered surveillance (periodic clinical, laboratory, and ultrasound evaluations). ACTs detected by imaging were surgically resected. Results: Of 180,000 newborns offered screening, 171,649 were screened, and 461 (0.27%) were carriers. As of April 2012, ACTs had been diagnosed in 11 of these carriers but in only two neonatally screened noncarriers (P < .001); six patient cases were identified among 228 carrier relatives age < 15 years (total, 19 ACTs). Surveillance participants included 347 (49.6%) of 699 carriers. Tumors were smaller in surveillance participants (P < .001) and more advanced in nonparticipants (four with stage III disease; two deaths). Neonatally screened carriers also had neuroblastoma (n = 1), glioblastoma multiforme (n = 1), choroid plexus carcinoma (n = 2), and Burkitt lymphoma (n = 1). Cancer histories and pedigrees were obtained for 353 families that included 1,704 identified carriers. ACTs were the most frequent cancer among carrier children (n = 48). Conclusion: These findings establish the prevalence of the TP53 R337H mutation in Paraná state and the penetrance of ACTs among carriers. Importantly, screening and surveillance of heterozygous carriers are effective in detecting ACTs when readily curable.

Steroidogenic factor-1 (SF-1/Ad4BP; NR5A1), a nuclear receptor transcription factor, has a pivotal role in adrenal and gonadal development in humans and mice. A frequent feature of childhood adrenocortical tumors is SF-1 amplification and overexpression. Here we show that an increased SF-1 dosage can by itself augment human adrenocortical cell proliferation through concerted actions on the cell cycle and apoptosis. This effect is dependent on an intact SF-1 transcriptional activity. Gene expression profiling showed that an increased SF-1 dosage regulates transcripts involved in steroid metabolism, the cell cycle, apoptosis, and cell adhesion to the extracellular matrix. Consistent with these results, increased SF-1 levels selectively modulate the steroid secretion profile of adrenocortical cells, reducing cortisol and aldosterone production and maintaining dehydroepiandrosterone sulfate secretion. As a model to understand the mechanisms of transcriptional regulation by increased SF-1 dosage, we studied FATE1, coding for a cancer-testis antigen implicated in the control of cell proliferation. Increased SF-1 levels increase its binding to a consensus site in FATE1 promoter and stimulate its activity through modulation of the recruitment of specific cofactors. On the other hand, sphingosine, which can compete with phospholipids for binding to SF-1, had no effect on the SF-1 dosage-dependent increase of adrenocortical cell proliferation and expression of the FATE1 promoter. In mice, increased Sf-1 dosage produces adrenocortical hyperplasia and formation of tumors expressing gonadal markers (Amh, Gata-4), which originate from the subcapsular region of the adrenal cortex. Gene expression profiling revealed that genes involved in cell adhesion and the immune response and transcription factor signal transducer and activator of transcription-3 (Stat3) are differentially expressed in Sf-1 transgenic mouse adrenals compared with wild-type adrenals. Our studies reveal a critical role for SF-1 dosage in adrenocortical tumorigenesis and constitute a rationale for the development of drugs targeting SF-1 transcriptional activity for adrenocortical tumor therapy.

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.

MicroRNAs (miRNAs) act at the posttranscriptional level to control gene expression in virtually every biological process, including oncogenesis. Here, we report the identification of a set of miRNAs that are differentially regulated in childhood adrenocortical tumors (ACT), including miR-99a and miR-100. Functional analysis of these miRNAs in ACT cell lines showed that they coordinately regulate expression of the insulin-like growth factor–mammalian target of rapamycin (mTOR)–raptor signaling pathway through binding sites in their 3′-untranslated regions. In these cells, the active Ser²⁴⁴⁸-phosphorylated form of mTOR is present only in mitotic cells in association with the mitotic spindle and midbody in the G₂-M phases of the cell cycle. Pharmacologic inhibition of mTOR signaling by everolimus greatly reduces tumor cell growth in vitro and in vivo. Our results reveal a novel mechanism of regulation of mTOR signaling by miRNAs, and they lay the groundwork for clinical evaluation of drugs inhibiting the mTOR pathway for treatment of adrenocortical cancer. Cancer Res; 70(11); 4666–75. ©2010 AACR.