p53 as a prognostic factor in adrenocortical tumors of adults and children

Adrenocortical Carcinoma in Childhood: A Systematic Review

Adrenocortical tumors are rare in children. This systematic review summarizes the published evidence on pediatric adrenocortical carcinoma (ACC) to provide a basis for a better understanding of the disease, investigate new molecular biomarkers and therapeutic targets, and define which patients may benefit from a more aggressive therapeutic approach. We included 137 studies with 3680 ACC patients (~65% female) in our analysis. We found no randomized controlled trials, so this review mainly reflects retrospective data. Due to a specific mutation in the TP53 gene in ~80% of Brazilian patients, that cohort was analyzed separately from series from other countries. Hormone analysis was described in 2569 of the 2874 patients (89%). Most patients were diagnosed with localized disease, whereas 23% had metastasis at primary diagnosis. Only 72% of the patients achieved complete resection. In 334 children (23%), recurrent disease was reported: 81%-local recurrence, 19% (n = 65)-distant metastases at relapse. Patients < 4 years old had a different distribution of tumor stages and hormone activity and better overall survival (p < 0.001). Although therapeutic approaches are typically multimodal, no consensus is available on effective standard treatments for advanced ACC. Thus, knowledge regarding pediatric ACC is still scarce and international prospective studies are needed to implement standardized clinical stratifications and risk-adapted therapeutic strategies.

Metastatic and recurrent adrenocortical cancer is not defined by its genomic landscape

Background

Adrenocortical carcinoma (ACC) is a rare, often-aggressive neoplasm of the adrenal cortex, with a 14–17 month median overall survival. We asked whether tumors from patients with advanced or metastatic ACC would offer clues as to putative genes that might have critical roles in disease progression or in more aggressive disease biology.

Methods

We conducted comprehensive genomic and expression analyses of ACCs from 43 patients, 30 female, and 42 from metastatic sites, including deep sequencing, copy number analysis, mRNA expression and microRNA arrays.

Results

Copy number gains and losses were similar to that previously reported for ACC. We identified a median mutation rate of 3.38 per megabase (Mb). The mutational signature was characterized by a predominance of C > T, C > A and T > C transitions. Only cancer genes TP53 (26%) and beta-catenin (CTNNB1, 14%) were mutated in more than 10% of samples. The TCGA-identified putative cancer genes MEN1 and PRKAR1A were found in low frequency—4.7 and 2.3%, respectively. The majority of the mutations were in genes not implicated in the etiology or maintenance of cancer. Specifically, amongst the 38 genes that were mutated in more than 9% of samples, only four were represented in Tier 1 of the 576 COSMIC Cancer Gene Census (CCGC). Thus, 82% of genes found to have mutations likely have no role in the etiology or biology of ACC; while the role of the other 18%, if any, remains to be proven. Finally, the transcript length for the 38 most frequently mutated genes in ACC is statistically longer than the average of all coding genes, raising the question of whether transcript length in part determined mutation probability.

Conclusions

We conclude that the mutational and expression profiles of advanced and metastatic tumors are very similar to those from newly diagnosed patients—with very little in the way of genomic aberration to explain differences in biology. With relatively low mutation rates, few major oncogenic drivers, and loss of function mutations in several epigenetic regulators, an epigenetic basis for ACC may be postulated and serve as the basis for future studies.

Somatic TP53 mutations are relatively rare among adrenocortical cancers with the frequent 17p13 loss of heterozygosity

PURPOSE

Allelic losses [loss of heterozygosity (LOH)] at the 17p13 locus are frequent (85%) in adrenocortical cancers. The tumor suppressor gene TP53 is located at 17p13. The aim of the study was to determine the frequency of TP53 somatic inactivating mutations in adrenocortical tumors with 17p13 LOH and their clinico-biological correlations.

EXPERIMENTAL DESIGN

TP53 somatic mutations, intragenic LOH (VNTR1 marker), and p53 overexpression were studied in 36 adrenocortical tumors with 17p13 LOH determined by Southern blot.

RESULTS

TP53 mutations were detected in 33% of the tumors, and VNTR1 LOH was present in 44% of the cases and did not always correlate with the presence of a TP53 mutation. Only the TP53-mutant tumors exhibit a strong nuclear immunoreactivity. TP53-mutant tumors were significantly larger than wild-type TP53 tumors (median tumor weight: 640 versus 185 g; P=0.02), were associated with a more advanced stage of tumor progression (MacFarlane stage IV; P=0.01), and had a shorter disease-free survival (P=0.03).

CONCLUSIONS

The finding that only a minority of adrenocortical tumors with 17p13 LOH had either a VNTR1 LOH or a TP53 mutation indicates that TP53 might not be the only or major tumor suppressor gene at 17p13 involved in adrenocortical cancer progression. We suggest that a genetic instability of the 17p13 region, occurring early in adrenocortical cancer development, involves various genes located in this region. TP53 might be only one of them, and its alteration by the occurrence of inactivating mutation is associated with the development of more aggressive tumors.

Childhood adrenocortical tumours: a review

Childhood adrenocortical tumour (ACT) is not a common disease, but in southern Brazil the prevalence is 15 times higher than in other parts of the world. One hundred and thirty-seven patients have been identified and followed by our group over the past four decades. Affected children are predominantly girls, with a female-to-male ratio of 3.5:1 in patients below 4 years of age. Virilization alone (51.6%) or mixed with Cushing's syndrome (42.0%) was the predominant clinical picture observed in these patients. Tumours are unilateral, affecting both glands equally. TP53 R337H germline mutations underlie most childhood ACTs in southern Brazil. Epidemiological data from our casuistic studies revealed that this mutation has ~10% penetrance for ACT. Surgery is the definitive treatment, and a complete resection should always be attempted. Although adjuvant chemotherapy has shown some encouraging results, its influence on overall outcome is small. The survival rate is directly correlated to tumour size; patients with small, completely excised tumours have survival rates close to 90%, whereas in those patients with inoperable tumours and/or metastatic disease it is less than 10%. In the group of patients with large, excisable tumours, half of them have an intermediate outcome. Recent molecular biology techniques and genomic approaches may help us to better understand the pathogenesis of ACT, the risk of developing a tumour when TP53 R337H is present, and to predict its outcome. An ongoing pilot study consisting of close monitoring of healthy carriers of the TP53 R337H mutation - siblings and first-degree relatives of known affected cases - aims at the early detection of ACTs and an improvement of the cure rate.

Virilizing Adrenocortical Carcinoma Invading the Right Atrium with Histological High-Grade Malignancy and p53 Mutation in a 3-Year-Old Child: Indication of Post Operative Adjuvant Chemotherapy

We present a 3-yr-old girl with a virilizing adrenocortical carcinoma invading into the right atrium with histological high-grade malignancy and p53 mutation. Development of facial acne and pubic hair were noted at 3 yr and 2 mo. The levels of androgens were high. Diurnal variation in ACTH and cortisol were absent. Abdominal computed tomography revealed a large right suprarenal mass, with extension into the inferior vena cava and right atrium. Based on the diagnosis of a right virilizing adrenocortical tumor with Cushing syndrome, surgery was performed by a combined thoracoabdominal approach with the patient on cardiopulmonary bypass. The tumor was 7 × 5.5 × 3.5 cm in size, and weighed 95 g. The histological diagnosis was adrenocartical carcinoma with high-grade malignancy according to the category of Weiss. A heterozygous mutation of the p53 tumor-suppressor gene (codon 248 CGC→TGG) was found. We did not perform adjuvant chemotherapy because of radical resection on macroscopic observation and no metastasis in radiological findings. Five months after the surgery, her chest X ray and computed tomography revealed multiple lung metastases and a single liver metastasis. In this type of patient with histological high-grade malignancy and p53 mutations, postoperative adjuvant chemotherapy is indicated even if macroscopic total surgical removal had been performed.

Management of adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a rare neoplasm with poor prognosis. Patients present with signs of steroid hormone excess (e.g. Cushing's syndrome, virilization) or an abdominal mass. Tumour size at presentation (mean diameter at diagnosis > 10 cm) is the most important indicator of malignancy. In addition, computed tomography (CT) typically demonstrates an inhomogeneous adrenal lesion with irregular margins and variable enhancement of solid components after intravenous contrast media. Magnetic resonance imaging (MRI) is equally effective as CT and is particularly helpful to visualize invasion into large vessels. Complete tumour removal (R0 resection) offers by far the best chance for long-term survival and therefore surgery is the treatment of choice in stage I-III ACC. Despite tumour resection for cure most patients will eventually develop local recurrence or distant metastases. Thus adjuvant treatment options need to be evaluated in high-risk patients (e.g. radiation therapy of the tumour bed and/or chemotherapy). In tumour recurrence re-operation should always be considered. In metastatic disease (stage IV ACC) not amenable to surgery mitotane (o,p'DDD) remains the first-line therapy. Drug monitoring is needed for effective treatment aiming at concentrations between 14 and 20 mg/l. Patients not responding to mitotane may benefit from cytotoxic chemotherapy (23% partial remissions, 4% complete remissions). Only large prospective multicentre trials comparing different treatment options will allow to make systematic progress in the management of ACC.