Gene expression profiling in adrenocortical neoplasia

Transcriptome Profile of the Rat Adrenal Gland: Parenchymal and Interstitial Cells

The homeostasis of the adrenal gland plays a decisive role in its proper functioning, both in non-stressful conditions and under the influence of various types of stress. This consists of interactions between all types of cells that make up the organ, including parenchymal and interstitial cells. The amount of available information on this subject in the rat adrenal glands under non-stressful conditions is insufficient; the aim of the research was to determine the expression of marker genes for rat adrenal cells depending on their location. The material for the study consisted of adrenal glands taken from intact adult male rats that were separated into appropriate zones. Transcriptome analysis by means of Affymetrix^® Rat Gene 2.1 ST Array was used in the study, followed by real-time PCR validation. Expression analysis of interstitial cell marker genes revealed both the amount of expression of these genes and the zone in which they were expressed. The expression of marker genes for fibroblasts was particularly high in the cells of the ZG zone, while the highest expression of specific macrophage genes was observed in the adrenal medulla. The results of this study, especially with regard to interstitial cells, provide a so far undescribed model of marker gene expression of various cells, both in the cortex and medulla of the sexually mature rat adrenal gland. The interdependence between parenchymal and interstitial cells creates a specific microenvironment that is highly heterogeneous within the gland with respect to some of the interstitial cells. This phenomenon most likely depends on the interaction with the differentiated parenchymal cells of the cortex, as well as the medulla of the gland.

Hereditary Endocrine Tumor Registries

Context

Endocrine neoplasia syndromes are phenotypically complex, and there is a misconception that they are universally rare. Genetic alterations are increasingly recognized; however, true prevalence is unknown. The purpose of a clinical registry is to monitor the quality of health care delivered to a specified group of patients through the collection, analysis, and reporting of relevant health-related information. This leads to improved clinical practice, decision-making, patient satisfaction, and outcome.

Objective

This review aims to identify, compare, and contrast active registries worldwide that capture data relevant to hereditary endocrine tumors (HETs).

Methods

Clinical registries were identified using a systematic approach from publications (Ovid MEDLINE, EMBASE) peer consultation, clinical trials, and web searches. Inclusion criteria were hereditary endocrine tumors, clinical registries, and English language. Exclusion criteria were institutional audits, absence of clinical data, or inactivity. Details surrounding general characteristics, funding, data fields, collection periods, and entry methods were collated.

Results

Fifteen registries specific for HET were shortlisted with 136 affiliated peer-reviewed manuscripts.

Conclusion

There are few clinical registries specific to HET. Most of these are European, and the data collected are highly variable. Further research into their effectiveness is warranted. We note the absence of an Australian registry for all HET, which would provide potential health and economic gains. This review presents a unique opportunity to harmonize registry data for HET locally and further afield.

FGF/FGFR signaling in adrenocortical development and tumorigenesis: novel potential therapeutic targets in adrenocortical carcinoma

FGF/FGFR signaling regulates embryogenesis, angiogenesis, tissue homeostasis and wound repair by modulating proliferation, differentiation, survival, migration and metabolism of target cells. Understandably, compelling evidence for deregulated FGF signaling in the development and progression of different types of tumors continue to emerge and FGFR inhibitors arise as potential targeted therapeutic agents, particularly in tumors harboring aberrant FGFR signaling. There is first evidence of a dual role of the FGF/FGFR system in both organogenesis and tumorigenesis, of which this review aims to provide an overview. FGF-1 and FGF-2 are expressed in the adrenal cortex and are the most powerful mitogens for adrenocortical cells. Physiologically, they are involved in development and maintenance of the adrenal gland and bind to a family of four tyrosine kinase receptors, among which FGFR1 and FGFR4 are the most strongly expressed in the adrenal cortex. The repeatedly proven overexpression of these two FGFRs also in adrenocortical cancer is thus likely a sign of their participation in proliferation and vascularization, though the exact downstream mechanisms are not yet elucidated. Thus, FGFRs potentially offer novel therapeutic targets also for adrenocortical carcinoma, a type of cancer resistant to conventional antimitotic agents.

The Role of Immunohistochemical Markers for the Diagnosis and Prognosis of Adrenocortical Neoplasms

Adrenal cortical carcinoma (ACC) is a rare cancer with poor prognosis that needs to be distinguished from adrenocortical adenomas (ACAs). Although, the recently developed transcriptome analysis seems to be a reliable tool for the differential diagnosis of adrenocortical neoplasms, it is not widely available in clinical practice. We aim to evaluate histological and immunohistochemical markers for the distinction of ACCs from ACAs along with assessing their prognostic role. Clinical data were retrospectively analyzed from 37 patients; 24 archived, formalin-fixed, and paraffin-embedded ACC samples underwent histochemical analysis of reticulin and immunohistochemical analysis of p27, p53, Ki-67 markers and were compared with 13 ACA samples. Weiss and Helsinki scores were also considered. Kaplan-Meier and univariate Cox regression methods were implemented to identify prognostic effects. Altered reticulin pattern, Ki-67% labelling index and overexpression of p53 protein were found to be useful histopathological markers for distinguishing ACAs from ACCs. Among the studied markers, only pathological p53 nuclear protein expression was found to reach statistically significant association with poor survival and development of metastases, although in a small series of patients. In conclusion, altered reticulin pattern and p53/Ki-67 expression are useful markers for distinguishing ACCs from ACAs. Immunohistopathology alone cannot discriminate ACCs with different prognosis and it should be combined with morphological criteria and transcriptome analysis.

Targeted RNAseq of Formalin-Fixed Paraffin-Embedded Tissue to Differentiate Among Benign and Malignant Adrenal Cortical Tumors

Lack of routine fresh or frozen tissue is a barrier to widespread transcriptomic analysis of adrenal cortical tumors and an impediment to translational research in endocrinology and endocrine oncology. Our group has previously pioneered the use of targeted amplicon-based next-generation sequencing for archival formalin-fixed paraffin-embedded (FFPE) adrenal tissue specimens to characterize the spectrum of somatic mutations in various forms of primary aldosteronism. Herein, we developed and validated a novel 194-amplicon targeted next-generation RNA sequencing (RNAseq) assay for transcriptomic analysis of adrenal tumors using clinical-grade FFPE specimens. Targeted RNAseq-derived expression values for 27 adrenal cortical tumors, including aldosterone-producing adenomas (APA; n=8), cortisol-producing adenomas (CPA; n=11), and adrenal cortical carcinomas (ACC; n=8), highlighted known differentially-expressed genes (DEGs; i. e., CYP11B2, IGF2, etc.) and tumor type-specific transcriptional modules (i. e., high cell cycle/proliferation transcript expression in ACC, etc.), and a subset of DEGs was validated orthogonally using quantitative reverse transcription PCR (qRT-PCR). Finally, unsupervised hierarchical clustering using a subset of high-confidence DEGs revealed three discrete clusters representing APA, CPA, and ACC tumors with corresponding unique gene expression signatures, suggesting potential clinical utility for a transcriptomic-based approach to tumor classification. Overall, these data support the use of targeted amplicon-based RNAseq for comprehensive transcriptomic profiling of archival FFPE adrenal tumor material and indicate that this approach may facilitate important translational research opportunities for the study of these tumors.

Non-Coding RNAs in Adrenocortical Cancer: From Pathogenesis to Diagnosis

Non-coding RNA molecules including microRNAs and long non-coding RNAs (lncRNA) have been implicated in the pathogenesis of several tumors and numerous data support their applicability in diagnosis as well. Despite recent advances, the pathogenesis of adrenocortical cancer still remains elusive and there are no reliable blood-borne markers of adrenocortical malignancy, either. Several findings show the potential applicability of microRNAs as biomarkers of malignancy and prognosis, and there are some data on lncRNA as well. In this review, we present a synopsis on the potential relevance of non-coding RNA molecules in adrenocortical pathogenesis and their applicability in diagnosis from tissue and blood.

Diagnostic and Prognostic Biomarkers of Adrenal Cortical Carcinoma

The diagnosis of low-grade adrenal cortical carcinoma (ACC) confined to the adrenal gland can be challenging. Although there are diagnostic and prognostic molecular tests for ACC, they remain largely unutilized. We examined the diagnostic and prognostic value of altered reticulin framework and the immunoprofile of biomarkers including IGF-2, proteins involved in cell proliferation and mitotic spindle regulation (Ki67, p53, BUB1B, HURP, NEK2), DNA damage repair (PBK, γ-H2AX), telomere regulation (DAX, ATRX), wnt-signaling pathway (beta-catenin) and PI3K signaling pathway (PTEN, phospho-mTOR) in a tissue microarray of 50 adenomas and 43 carcinomas that were characterized for angioinvasion as defined by strict criteria, Weiss score, and mitotic rate-based tumor grade. IGF-2 and proteins involved in cell proliferation and mitotic spindle regulation (Ki67, p53, BUB1B, HURP, NEK2), DNA damage proteins (PBK, γ-H2AX), regulators of telomeres (DAXX, ATRX), and beta-catenin revealed characteristic expression profiles enabling the distinction of carcinomas from adenomas. Not all biomarkers were informative in all carcinomas. IGF-2 was the most useful biomarker of malignancy irrespective of tumor grade and cytomorphologic features, as juxtanuclear Golgi-pattern IGF-2 reactivity optimized for high specificity was identified in up to 80% of carcinomas and in no adenomas. Loss rather than qualitative alterations of the reticulin framework yielded statistical difference between carcinoma and adenoma. Angioinvasion defined as tumor cells invading through a vessel wall and intravascular tumor cells admixed with thrombus proved to be the best prognostic parameter, predicting adverse outcome in the entire cohort as well as within low-grade ACCs. Low mitotic tumor grade, Weiss score, global loss of DAXX expression, and high phospho-mTOR expression correlated with disease-free survival, but Weiss score and biomarkers failed to predict adverse outcome in low-grade disease. Our results underscore the importance of careful morphologic assessment coupled with ancillary diagnostic and prognostic biomarkers of ACC.

Immunohistochemical Biomarkers of Adrenal Cortical Neoplasms

Careful morphological evaluation forms the basis of the workup of an adrenal cortical neoplasm. However, the adoption of immunohistochemical biomarkers has added tremendous value to enhance diagnostic accuracy. The authors provide a brief review of immunohistochemical biomarkers that have been used in the confirmation of adrenal cortical origin and in the detection of the source of functional adrenal cortical proliferations, as well as diagnostic, predictive, and prognostic biomarkers of adrenal cortical carcinoma. In addition, a brief section on potential novel theranostic biomarkers in the prediction of treatment response to mitotane and other relevant chemotherapeutic agents is also provided. In the era of precision and personalized medical practice, adoption of combined morphology and immunohistochemistry provides a new approach to the diagnostic workup of adrenal cortical neoplasms, reflecting the evolution of clinical responsibility of pathologists.

Genetics of tumors of the adrenal cortex

This review describes the molecular alterations observed in the various types of tumors of the adrenal cortex, excluding Conn adenomas, especially the alterations identified by genomic approaches these last five years. Two main forms of bilateral adrenocortical tumors can be distinguished according to size and aspect of the nodules: primary pigmented nodular adrenal disease (PPNAD), which can be sporadic or part of Carney complex and primary bilateral macro nodular adrenal hyperplasia (PBMAH). The bilateral nature of the tumors suggests the existence of an underlying genetic predisposition. PPNAD and Carney complex are mainly due to germline-inactivating mutations of PRKAR1A, coding for a regulatory subunit of PKA, whereas PBMAH genetic seems more complex. However, genome-wide approaches allowed the identification of a new tumor suppressor gene, ARMC5, whose germline alteration could be responsible for at least 25% of PBMAH cases. Unilateral adrenocortical tumors are more frequent, mostly adenomas. The Wnt/beta-catenin pathway can be activated in both benign and malignant tumors by CTNNB1 mutations and by ZNRF3 inactivation in adrenal cancer (ACC). Some other signaling pathways are more specific of the tumor dignity. Thus, somatic mutations of cAMP/PKA pathway genes, mainly PRKACA, coding for the catalytic alpha-subunit of PKA, are found in cortisol-secreting adenomas, whereas IGF-II overexpression and alterations of p53 signaling pathway are observed in ACC. Genome-wide approaches including transcriptome, SNP, methylome and miRome analysis have identified new genetic and epigenetic alterations and the further clustering of ACC in subgroups associated with different prognosis, allowing the development of new prognosis markers.

Novel targeted therapies in adrenocortical carcinoma

PURPOSE OF REVIEW

Adrenocortical carcinoma is a rare cancer, but one that carries a poor prognosis due to its aggressive nature and unresponsiveness to conventional chemotherapeutic strategies. Over the past 12 years, there has been renewed interest in developing new therapies for this cancer, including identifying key signaling nodes responsible for cell proliferation.

RECENT FINDINGS

Clinical trials of tyrosine kinase inhibitors as monotherapy have generally been disappointing, although the identification of exceptional responders may lead to the identification of targeted therapies that may produce responses in subsets of patients. Agents targeted to the Wnt signaling pathway, a known player in adrenal carcinogenesis, have been developed, although they have not yet been used specifically for adrenal cancer. There is current excitement about inhibitors of acetyl-coA cholesterol acetyl transferase 1, an enzyme required for intracellular cholesterol handling, although trials are still underway. Tools to target other proteins such as Steroidogenic Factor 1 and mechanistic target of rapamycin have been developed and are moving towards clinical application.

SUMMARY

Progress is being made in the fight against adrenocortical carcinoma with the identification of new therapeutic targets and new means by which to attack them. Continued improvement in the prognosis for patients with adrenal cancer is expected as this research continues.

Mouse models of adrenocortical tumors

The molecular basis of the organogenesis, homeostasis, and tumorigenesis of the adrenal cortex has been the subject of intense study for many decades. Specifically, characterization of tumor predisposition syndromes with adrenocortical manifestations and molecular profiling of sporadic adrenocortical tumors have led to the discovery of key molecular pathways that promote pathological adrenal growth. However, given the observational nature of such studies, several important questions regarding the molecular pathogenesis of adrenocortical tumors have remained. This review will summarize naturally occurring and genetically engineered mouse models that have provided novel tools to explore the molecular and cellular underpinnings of adrenocortical tumors. New paradigms of cancer initiation, maintenance, and progression that have emerged from this work will be discussed.

The genetics of adrenocortical tumors

Advances in genomics accelerated greatly progress in the study of the genetics adrenocortical tumors. Bilateral nodular hyperplasias causing Cushing's syndrome are frequently caused by germline alterations leading to cAMP/PKA pathway activation (micronodular) and ARMC5 inactivation (macronodular). Somatic mutations of β-catenin and PRKACA are observed in non secreting or cortisol producing adenomas, respectively. Alterations of the β-catenin (CTNN1B, ZNFR3) or TP53 pathways are found in carcinomas. Mutations in cancers are more common in aggressive tumors and correlate with transcriptome or methylation profiles. Identification of these alterations helps to refine the molecular classification of these tumors and to develop molecular diagnostic tools.

Long noncoding RNA profiles of adrenocortical cancer can be used to predict recurrence

Adrenocortical carcinoma (ACC) is an aggressive malignancy with high rates of recurrence following surgical resection. Long noncoding RNAs (lncRNAs) play an important role in cancer development. Pathogenesis of adrenal tumours have been characterised by mRNA, microRNA and methylation expression signatures, but it is unknown if this extends to lncRNAs. This study describes lncRNA expression signatures in ACC, adrenal cortical adenoma (ACA) and normal adrenal cortex (NAC) and presents lncRNAs associated with ACC recurrence to identify novel prognostic and therapeutic targets. RNA was extracted from freshly frozen tissue with confirmation of diagnosis by histopathology. Focused lncRNA and mRNA transcriptome analysis was performed using the ArrayStar Human LncRNA V3.0 microarray. Differentially expressed lncRNAs were validated using quantitative reverse transcriptase-PCR and correlated with clinical outcomes. Microarray of 21 samples (ten ACCs, five ACAs and six NACs) showed distinct patterns of lncRNA expression between each group. A total of 956 lncRNAs were differentially expressed between ACC and NAC, including known carcinogenesis-related lncRNAs such as H19, GAS5, MALAT1 and PRINS (P≤0.05); 85 lncRNAs were differentially expressed between ACC and ACA (P≤0.05). Hierarchical clustering and heat mapping showed ACC samples correctly grouped compared with NAC and ACA. Sixty-six differentially expressed lncRNAs were found to be associated with ACC recurrence (P≤0.05), one of which, PRINS, was validated in a group of 20 ACCs and also found to be associated with metastatic disease on presentation. The pathogenesis of adrenal tumours extends to lncRNA dysregulation and low expression of the lncRNA PRINS is associated with ACC recurrence.

Adrenocortical growth and cancer

The adrenal gland consists of two distinct parts, the cortex and the medulla. Molecular mechanisms controlling differentiation and growth of the adrenal gland have been studied in detail using mouse models. Knowledge also came from investigations of genetic disorders altering adrenal development and/or function. During embryonic development, the adrenal cortex acquires a structural and functional zonation in which the adrenal cortex is divided into three different steroidogenic zones. Significant progress has been made in understanding adrenal zonation. Recent lineage tracing experiments have accumulated evidence for a centripetal differentiation of adrenocortical cells from the subcapsular area to the inner part of the adrenal cortex. Understanding of the mechanism of adrenocortical cancer (ACC) development was stimulated by knowledge of adrenal gland development. ACC is a rare cancer with a very poor overall prognosis. Abnormal activation of the Wnt/β-catenin as well as the IGF2 signaling plays an important role in ACC development. Studies examining rare genetic syndromes responsible for familial ACT have played an important role in identifying genetic alterations in these tumors (like TP53 or CTNNB1 mutations as well as IGF2 overexpression). Recently, genomic analyses of ACT have shown gene expression profiles associated with malignancy as well as chromosomal and methylation alterations in ACT and exome sequencing allowed to describe the mutational landscape of these tumors. This progress leads to a new classification of these tumors, opening new perspectives for the diagnosis and prognostication of ACT. This review summarizes current knowledge of adrenocortical development, growth, and tumorigenesis.

Assessing Biological Aggression in Adrenocortical Neoplasia

Pathologists are highly skilled at the evaluation of adrenal neoplasms. Occasional adrenocortical tumors can be diagnostically challenging and supplementary tools can assist in these cases. Histologic and molecular studies support a model that includes 2 broad classes of adrenocortical carcinoma with distinct somatic genetic alterations and clinical outcomes. Pathologists should endeavor to grade adrenocortical carcinomas to assign each case into one of these 2 classes. Mitotic grading by mitotic counting and Ki-67 immunohistochemistry represent the most practicable and informative methods currently available.

Emerging therapy for adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a very rare and aggressive tumor with dismal outcomes. Best current treatments include complete surgical resection for localized resectable disease and systemic therapy with mitotane alone or in combination for advanced ACC. Advances in molecular genetic profiling of ACC have created multiple new targets for potential treatment options in ACC. This article reviews the current treatment options available for ACC and discusses the potential new targets identified through molecular profiling.

Next-generation sequencing of adrenocortical carcinoma reveals new routes to targeted therapies

Aims

Adrenocortical carcinoma (ACC) carries a poor prognosis and current systemic cytotoxic therapies result in only modest improvement in overall survival. In this retrospective study, we performed a comprehensive genomic profiling of 29 consecutive ACC samples to identify potential targets of therapy not currently searched for in routine clinical practice.

Methods

DNA from 29 ACC was sequenced to high, uniform coverage (Illumina HiSeq) and analysed for genomic alterations (GAs).

Results

At least one GA was found in 22 (76%) ACC (mean 2.6 alterations per ACC). The most frequent GAs were in TP53 (34%), NF1 (14%), CDKN2A (14%), MEN1 (14%), CTNNB1 (10%) and ATM (10%). APC, CCND2, CDK4, DAXX, DNMT3A, KDM5C, LRP1B, MSH2 and RB1 were each altered in two cases (7%) and EGFR, ERBB4, KRAS, MDM2, NRAS, PDGFRB, PIK3CA, PTEN and PTCH1 were each altered in a single case (3%). In 17 (59%) of ACC, at least one GA was associated with an available therapeutic or a mechanism-based clinical trial.

Conclusions

Next-generation sequencing can discover targets of therapy for relapsed and metastatic ACC and shows promise to improve outcomes for this aggressive form of cancer.

MicroRNA expression patterns associated with hyperfunctioning and non-hyperfunctioning phenotypes in adrenocortical adenomas

BACKGROUND

The adrenocortical adenoma (ACA) entity includes aldosterone-producing adenoma (APA), cortisol-producing adenoma (CPA), and non-hyperfunctioning adenoma (NHFA) phenotypes. While gene mutations and mRNA expression profiles have been partly characterized, less is known about the alterations involving microRNA (miRNA) expression.

AIM

To characterize miRNA expression profile in relation to the subtypes of ACAs.

SUBJECTS AND METHODS

miRNA expression profiles were determined in 26 ACAs (nine APAs, ten CPAs, and seven NHFAs) and four adrenal references using microarray-based screening. Significance analysis of microarrays (SAM) was carried out to identify differentially expressed miRNAs between ACA and adrenal cortices or between tumor subtypes. Selected differentially expressed miRNAs were validated in an extended series of 43 ACAs and ten adrenal references by quantitative RT-PCR.

RESULTS

An hierarchical clustering revealed separate clusters for APAs and CPAs, while the NHFAs were found spread out within the APA/CPA clusters. When NHFA was excluded, the clustering analysis showed a better separation between APA and CPA. SAM analysis identified 40 over-expressed and three under-expressed miRNAs in the adenomas as compared with adrenal references. Fourteen miRNAs were common among the three ACA subtypes. Furthermore, we found specific miRNAs associated with different tumor phenotypes.

CONCLUSION

The results suggest that miRNA expression profiles can distinguish different subtypes of ACA, which may contribute to a deeper understanding of ACA development and potential therapeutics.

Adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy, often with an unfavorable prognosis. Here we summarize the knowledge about diagnosis, epidemiology, pathophysiology, and therapy of ACC. Over recent years, multidisciplinary clinics have formed and the first international treatment trials have been conducted. This review focuses on evidence gained from recent basic science and clinical research and provides perspectives from the experience of a large multidisciplinary clinic dedicated to the care of patients with ACC.

The 'omics' of adrenocortical tumours for personalized medicine

Pan-genomic analyses of genetic and epigenetic alterations and gene expression profiles are providing important new insights into the pathogenesis and molecular classification of cancers. The technologies and methods used for these studies are rapidly diversifying and improving. The use of such methodologies for the analysis of adrenocortical tumours has revealed clear transcriptomic (mRNA and microRNA expression profiles), epigenomic (DNA methylation profiles) and genomic (DNA mutations and chromosomal alterations) differences between benign and malignant tumours. Interestingly, genomic studies of adrenal cancers have also identified subtypes of malignant tumours, which demonstrate distinct patterns of molecular alterations and are associated with different clinical outcomes. These discoveries have created the opportunity for classifying adrenocortical tumours on the basis of molecular analyses. Following these genomic studies, efforts to develop new molecular tools that improve diagnosis and prognostication of patients with adrenocortical tumours have also been made. This Review describes the progress that has been made towards classification of adrenocortical tumours to date based on key genomic approaches. In addition, the potential for the development and use of various molecular tools to personalize the management of patients with adrenocortical tumours is discussed.

Pathology of the adrenal cortex: a reappraisal of the past 25 years focusing on adrenal cortical tumors

A reappraisal of the major advances in the diagnostic pathology of adrenal cortical lesions and tumors in the last 25 years is presented, with special reference to the definition of malignancy in primary adrenal cancer and its variants. Slightly more than 25 years ago, Weiss proposed his diagnostic scoring system for adrenal cortical carcinoma. This represented a milestone for adrenal pathologists and the starting point for further modifications of the system, either through minor changes in the scoring procedure itself or concentrating on some particular Weiss criterion such as mitotic index, integrated into alternative scoring schemes or algorithms that are currently under validation. Improvements in diagnostic immunohistochemistry have led to the identification of markers of cortical origin, such as Melan-A, alpha-inhibin, and SF-1 and of prognostic factors in carcinoma, such as the Ki-67 proliferation index and SF-1 itself. With regard to hyperplastic conditions, genetic investigations have allowed the association of the majority of cases of primary pigmented nodular adrenocortical disease (PPNAD) in Carney complex to mutations in the gene encoding the regulatory subunit 1A of protein kinase A (PRKAR1A). Other hereditary conditions are also associated with adrenal cortical tumors, including the Li-Fraumeni, Beckwith-Wiedemann, Gardner, multiple endocrine neoplasia type 1, and neurofibromatosis type 1 syndromes. Moreover, several advances have been made in the knowledge of the molecular background of sporadic tumors, and a number of molecules/genes are of particular interest as potential diagnostic and prognostic biomarkers.

Autocrine/paracrine regulatory mechanisms in adrenocortical neoplasms responsible for primary adrenal hypercorticism

A wide variety of autocrine/paracrine bioactive signals are able to modulate corticosteroid secretion in the human adrenal gland. These regulatory factors, released in the vicinity of adrenocortical cells by diverse cell types comprising chromaffin cells, nerve terminals, cells of the immune system, endothelial cells, and adipocytes, include neuropeptides, biogenic amines, and cytokines. A growing body of evidence now suggests that paracrine mechanisms may also play an important role in the physiopathology of adrenocortical hyperplasias and tumors responsible for primary adrenal steroid excess. These intra-adrenal regulatory systems, although globally involving the same actors as those observed in the normal gland, display alterations at different levels, which reinforce the capacity of paracrine factors to stimulate the activity of adrenocortical cells. The main modifications in the adrenal local control systems reported by now include hyperplasia of cells producing the paracrine factors and abnormal expression of the latter and their receptors. Because steroid-secreting adrenal neoplasms are independent of the classical endocrine regulatory factors angiotensin II and ACTH, which are respectively suppressed by hyperaldosteronism and hypercortisolism, these lesions have long been considered as autonomous tissues. However, the presence of stimulatory substances within the neoplastic tissues suggests that steroid hypersecretion is driven by autocrine/paracrine loops that should be regarded as promising targets for pharmacological treatments of primary adrenal disorders. This new potential therapeutic approach may constitute an alternative to surgical removal of the lesions that is classically recommended in order to cure steroid excess.

Current management options for recurrent adrenocortical carcinoma

Adrenal cortical carcinoma (ACC) is a rare cancer that poses a number of management challenges due to the limited number of effective systemic treatments. Complete surgical resection offers the best chance of long-term survival. However, despite complete resection, ACC is associated with high recurrence rates. This review will discuss the management of recurrent ACC in adults following complete surgical resection. Management should take place in a specialist center and treatment decisions must consider the individual tumor biology of each case of recurrence. Given the fact that ACC commonly recurs, management to prevent recurrence should be considered from initial diagnosis with the use of adjuvant mitotane. Close follow up with clinical examination and imaging is important for early detection of recurrent disease. Locoregional recurrence may be isolated, and repeat surgical resection should be considered along with mitotane. The use of radiotherapy in ACC remains controversial. Systemic recurrence most often involves liver, pulmonary, and bone metastasis and is usually managed with mitotane, with or without combination chemotherapy. There is a limited role for surgical resection in systemic recurrence in selected patients. In all patients with recurrent disease, control of excessive hormone production is an important part of management. Despite intensive management of recurrent ACC, treatment failure is common and the use of clinical trials and novel treatment is an important part of management.

Identification of gene expression profiles associated with cortisol secretion in adrenocortical adenomas

CONTEXT

The cortisol secretion of adrenocortical adenomas can be either subtle or overt. The mechanisms leading to the autonomous hypersecretion of cortisol are unknown.

OBJECTIVE

The objective of the study was to identify the gene expression profile associated with the autonomous and excessive cortisol secretion of adrenocortical adenomas.

PATIENTS AND METHODS

The transcriptome of 22 unilateral adrenocortical adenomas (5 nonsecreting, 6 subclinical cortisol producing, 11 cortisol producing) was studied and correlated with cortisol secretion. Phosphodiesterase 8B (PDE8B) expression was measured by Western blot.

RESULTS

Unsupervised clustering identified 2 groups of adenomas with a difference in secretion level (P = .008). Cluster 1 included only cortisol-producing adenomas (8 of 11), whereas cluster 2 was an admixture of the nonsecreting, the subclinical cortisol-secreting, and 3 of the 11 cortisol-secreting adenomas (Fisher exact, P = .002). This cluster was driven by genes related to cortisol secretion and to extracellular matrix. More than 3000 genes correlated with cortisol secretion. Among the positively correlated were the steroidogenic enzymes, genes involved in cholesterol metabolism, and glutathione S-transferases. Among the negatively correlated genes were genes related to transcripts translation and the transcription factor GATA-6. The PDE8B, which inactivates the protein kinase A pathway, unexpectedly showed the strongest positive correlation with cortisol secretion, confirmed by Western blot. The protein kinase A-activity to cAMP ratio was increased in adenomas with high PDE8B levels, suggesting counterregulation to limit downstream activation of the pathway.

CONCLUSION

The transcriptome of adrenocortical adenomas reveals a major association with cortisol secretion and identifies specific groups of genes implicated in steroid secretion, suggesting that cAMP signaling alterations might be frequent in cortisol-secreting adenomas.

Adrenocortical Carcinoma: Current Therapeutic State-of-the-Art

Adrenocortical carcinoma (ACC) is a rare, aggressive malignancy that generally conveys a poor prognosis. Currently, surgical resection is considered the lone curative treatment modality. In addition, the low prevalence of ACC has limited effective clinical trial design to develop evidence-based approaches to ACC therapy. The proper role of radio- and chemotherapy treatment for ACC is still being defined. Similarly, the molecular pathogenesis of ACC remains to be fully characterized. Despite these challenges, progress has been made in several areas. After years of refinement, an internationally accepted staging system has been defined. International collaborations have facilitated increasingly robust clinical trials, especially regarding agent choice and patient selection for chemotherapeutics. Genetic array data and molecular profiling have identified new potential targets for rational drug design as well as potential tumor markers and predictors of therapeutic response. However, these advances have not yet been translated into a large outcomes benefit for ACC patients. In this paper, we summarize established therapy for ACC and highlight recent findings in the field that are impacting clinical practice.