Functional genomics approaches for the study of sporadic adrenal tumor pathogenesis: clinical implications

Molecular markers of adrenocortical tumors

Adrenocortical tumors are common and incidentally discovered in up to 14% of axial imaging studies performed for other indications. Most of these tumors are nonfunctioning but may require removal because of the risk of adrenocortical carcinoma. Unfortunately, most clinical and imaging features are still not accurate enough to allow definitive diagnosis and an increasing number of patients undergo adrenalectomy to exclude a cancer diagnosis. Adrenocortical carcinoma is an aggressive malignancy with no effective therapy for patients with locally advanced and metastatic disease. Studies using new genomic approaches including mRNA, miRNA, methylation, and CGH profiling have identified dysregulated genes and pathways that may have clinical implications in improved molecular diagnosis and prognostication of adrenocortical cancer (ACC). In this review, we highlight recent advances in the molecular diagnosis of adrenocortical tumors.

Genomics in pediatric endocrinology-genetic disorders and new techniques

In the last few years, there have been remarkable advances in the development of new and more sophisticated genetic techniques. These have allowed a better understanding of the molecular mechanisms of genetically determined pediatric endocrine disorders and are paving the way for a radical change in diagnosis and treatment. This article introduces some of these concepts and some of the genetic techniques being used.

Pathogenesis of adrenocortical cancer

A mellékvesekéreg-carcinoma ritka, rossz prognózisú daganat. Döntően sporadikus előfordulású, de ismertek nagyon ritka öröklődő formái is, amelyek a patogenezis megértésében nagy segítséget nyújtanak. A mellékvesekéreg-daganatokra hajlamosító öröklődő szindrómák közé tartozik a Li–Fraumeni-szindróma, a Beckwith–Wiedemann-szindróma, a familiáris adenomatosus polyposis, illetve a döntően benignus daganatokkal társuló multiplex endokrin neoplasia 1-es típusa (MEN1), Carney-komplex és McCune–Albright-szindróma. A mellékvesekéreg-daganatok patogenezisében szereplő főbb mechanizmusok közé tartozik az inzulinszerű növekedési faktor-2 fokozott expressziója, a Wnt/β-katenin és a cAMP-proteinkináz-A jelátviteli utak aktivációja, valamint a p53 és MEN1 gének mutációi. A mellékvesekéreg-carcinoma kezelésében a gyógyszeres lehetőségek meglehetősen korlátozottak. Az utóbbi évek molekuláris-bioinformatikai kutatásai számos eddig ismeretlen patogenetikai út szerepét vetették fel, amelyek új gyógyszeres támadáspontok lehetőségét is jelenthetik. E tanulmányban a szerzők az öröklődő daganatszindrómák patogenezisét, a sporadikus daganatokban észlelt eltéréseket és a legújabb molekuláris-bioinformatikai eredményeket ismertetik.

Genomics in pediatric endocrinology--genetic disorders and new techniques

In the last few years, there have been remarkable advances in the development of new and more sophisticated genetic techniques. These have allowed a better understanding of the molecular mechanisms of genetically determined pediatric endocrine disorders and are paving the way for a radical change in diagnosis and treatment. This article introduces some of these concepts and some of the genetic techniques being used.

Review paper: origin and molecular pathology of adrenocortical neoplasms

Neoplastic adrenocortical lesions are common in humans and several species of domestic animals. Although there are unanswered questions about the origin and evolution of adrenocortical neoplasms, analysis of human tumor specimens and animal models indicates that adrenocortical tumorigenesis involves both genetic and epigenetic alterations. Chromosomal changes accumulate during tumor progression, and aberrant telomere function is one of the key mechanisms underlying chromosome instability during this process. Epigenetic changes serve to expand the size of the uncommitted adrenal progenitor population, modulate their phenotypic plasticity (i.e., responsiveness to extracellular signals), and increase the likelihood of subsequent genetic alterations. Analyses of heritable and spontaneous types of human adrenocortical tumors documented alterations in either cell surface receptors or their downstream effectors that impact neoplastic transformation. Many of the mutations associated with benign human adrenocortical tumors result in dysregulated cyclic adenosine monophosphate signaling, whereas key factors and/or signaling pathways associated with adrenocortical carcinomas include dysregulated expression of the IGF2 gene cluster, activation of the Wnt/beta-catenin pathway, and inactivation of the p53 tumor suppressor. A better understanding of the factors and signaling pathways involved in adrenal tumorigenesis is necessary to develop targeted pharmacologic and genetic therapies.

Pathogenesis of adrenocortical cancer

The study of the clonality of adrenocortical tumours (ACTs) has shown that adrenocortical cancers (ACCs) are of monoclonal origin. Numerous chromosomal alterations have been observed in ACCs, and they are much more frequent than in adrenocortical adenomas. Progress in the genetics of familial syndromes associated with ACTs helped to identify significant somatic molecular alterations in sporadic adult ACCs. Somatic mutations of the tumour suppressor gene TP53 are observed in a third of ACCs. Interestingly, allelic losses (LOH) at the TP53 locus (17p13) are very frequent, observed in more than 85% of ACCs. The insulin-like growth factor II (IGF-II) locus (11p15) is imprinted. IGF-II is over-expressed in 90% of ACCs. Transcriptome studies have identified an IGF-II cluster of genes significantly over-expressed in ACCs. Transcriptome analysis suggests also that the Wnt/beta-catenin signalling pathway is activated in ACT. About a third of ACCs harbours somatic activating mutations of the beta-catenin gene. This recent progress in the molecular genetics of ACC has led to the development of new molecular markers for the diagnosis of malignancy; these might also help to identify prognostic markers of ACC and may ultimately lead to novel therapeutic approaches.