Advances in understanding the molecular underpinnings of adrenocortical tumors

The Role of Biomarkers in Adrenocortical Carcinoma: A Review of Current Evidence and Future Perspectives

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy arising from the adrenal cortex often with unexpected biological behavior. It can occur at any age, with two peaks of incidence: in the first and between fifth and seventh decades of life. Although ACC are mostly hormonally active, precursors and metabolites, rather than end products of steroidogenesis are produced by dedifferentiated and immature malignant cells. Distinguishing the etiology of adrenal mass, between benign adenomas, which are quite frequent in general population, and malignant carcinomas with dismal prognosis is often unfeasible. Even after pathohistological analysis, diagnosis of adrenocortical carcinomas is not always straightforward and represents a great challenge for experienced and multidisciplinary expert teams. No single imaging method, hormonal work-up or immunohistochemical labelling can definitively prove the diagnosis of ACC. Over several decades' great efforts have been made in finding novel reliable and available diagnostic and prognostic factors including steroid metabolome profiling or target gene identification. Despite these achievements, the 5-year mortality rate still accounts for approximately 75% to 90%, ACC is frequently diagnosed in advanced stages and therapeutic options are unfortunately limited. Therefore, imperative is to identify new biological markers that can predict patient prognosis and provide new therapeutic options.

Whole-Exome Sequencing of Syndromic Adrenocortical Carcinoma Reveals Distinct Mutational Profile From Sporadic ACC

Next-generation sequencing has provided genetic profiles of a large number of sporadic adrenocortical carcinomas (ACCs), but the applicability of these results to ACC cases associated with tumor predisposition syndromes is unclear. Although the germline features of these syndromes have been well described, the somatic mutational landscape of the tumors they give rise to is less clear. Our group obtained germline and tumor tissue from a pediatric patient who developed ACC during her first year of life, which was treated successfully. She was subsequently diagnosed with additional tumors later in childhood. Whole exome sequencing analysis was performed followed by in silico protein function prediction, revealing a probably deleterious germline TP53 L265P mutation. The somatic mutational burden was comparable between the index case and a previously published cohort of 40 sporadic cases, but the mutational spectrum was distinct in terms of raw base-change frequency as well as in a trinucleotide context-specific analysis. No canonical somatic genetic drivers of ACC were identified in the reported case, suggesting that syndromic adrenocortical tumors may represent a genetically distinct entity from sporadic tumors.

Adrenocortical cancer cell line mutational profile reveals aggressive genetic background

Adrenocortical carcinomas are rare tumors with poor prognosis and limited treatment options. Although widely used as in vitro models to test novel therapeutic strategies, the adrenocortical carcinoma-derived cell lines NCI-H295R and SW-13 have only partially been described genetically. Our aim was to characterize the mutational landscape of these cells to improve their experimental utility and map them to clinical subtypes of adrenocortical carcinoma. Genomic DNA from NCI-H295R and SW-13 cells was subjected to whole-exome sequencing. Variants were filtered for non-synonymous mutations and curated for validated adrenocortical and pan-cancer driver gene mutations. Genes mutated in the cell lines were mapped using gene ontology and protein pathway tools to determine signaling effects and compared to mutational and clinical characteristics of 92 adrenocortical carcinoma cases from The Cancer Genome Atlas. NCI-H295R and SW-13 cells carried 1325 and 1836 non-synonymous variants, respectively. Of these, 61 and 76 were known cancer driver genes, of which 32 were shared between cell lines. Variant interaction analyses demonstrated dominant TP53 dysregulation in both cell lines complemented by distinct WNT (NCI-H295R) and chromatin remodeling (SW-13) pathway perturbations. Both cell lines genetically resemble more aggressive adrenocortical carcinomas with worse prognosis, for which development of targeted therapies is most critical. Careful incorporation of the genetic landscapes outlined in this study will further the in vitro utility of these cell lines in testing for novel therapeutic approaches for adrenocortical malignancy.

Oncocytic Adrenocortical Neoplasm with Concomitant Papillary Thyroid Cancer

Adrenal oncocytoma (AO) is an extremely rare adrenocortical neoplasm and little is known about its malignant potential, secretory properties, and hereditary origin. We present the case of a benign AO with concomitant incidentally found papillary thyroid cancer (PTC) and review similar cases in the literature. Immunohistochemistry and next-generation sequencing (NGS) were performed. A 66-year-old women was incidentally found to have a large, androgen-secreting right adrenal mass. ¹⁸F-Fluorodeoxyglucose positron emission tomography showed intense uptake (SUV_max 88.7) of this mass and found a hypermetabolic right thyroid mass. Open adrenalectomy was performed for this highly suspicious adrenal mass. Histopathology revealed benign AO that was BRAF^V600E negative, with low Ki-67, and no somatic mutation found on NGS. Thyroidectomy revealed invasive, BRAF^V600E-positive PTC. At 6 months follow-up, androgen levels returned to normal, and no recurrence was seen on imaging. To our knowledge, this is the first report of an androgen-secreting AO with concomitant PTC. Possibly the simultaneous discovery of two independent neoplasms was observed. In conclusion, this case highlights that care should be given to exclude concomitant neoplasms. Long-term and regular imaging with biochemical follow-up is warranted, since the outcome and clinical behavior of AO remains uncertain.