Although the authors of the present review have contributed to genetic discoveries in the field of pheochromocytoma research, we can legitimately ask whether these advances have led to improvements in the diagnosis and management of patients with pheochromocytoma. The answer to this question is an emphatic Yes! In the field of molecular genetics, the well-established axiom that familial (genetic) pheochromocytoma represents 10% of all cases has been overturned, with >35% of cases now attributable to germline disease-causing mutations. Furthermore, genetic pheochromocytoma can now be grouped into five different clinical presentation types in the context of the ten known susceptibility genes for pheochromocytoma-associated syndromes. We now have the tools to diagnose patients with genetic pheochromocytoma, identify germline mutation carriers and to offer gene-informed medical management including enhanced surveillance and prevention. Clinically, we now treat an entire family of tumors of the paraganglia, with the exact phenotype varying by specific gene. In terms of detection and classification, simultaneous advances in biochemical detection and imaging localization have taken place, and the histopathology of the paraganglioma tumor family has been revised by immunohistochemical-genetic classification by gene-specific antibody immunohistochemistry. Treatment options have also been substantially enriched by the application of minimally invasive and adrenal-sparing surgery. Finally and most importantly, it is now widely recognized that patients with genetic pheochromocytoma/paraganglioma syndromes should be treated in specialized centers dedicated to the diagnosis, treatment and surveillance of this rare neoplasm.
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Hartmut P Neumann, William F Young Jr, Tobias Krauss, Jean-Pierre Bayley, Francesca Schiavi, Giuseppe Opocher, Carsten C Boedeker, Amit Tirosh, Frederic Castinetti, Juri Ruf, Dmitry Beltsevich, Martin Walz, Harald-Thomas Groeben, Ernst von Dobschuetz, Oliver Gimm, Nelson Wohllk, Marija Pfeifer, Delmar M Lourenço Jr, Mariola Peczkowska, Attila Patocs, Joanne Ngeow, Özer Makay, Nalini S Shah, Arthur Tischler, Helena Leijon, Gianmaria Pennelli, Karina Villar Gómez de las Heras, Thera P Links, Birke Bausch and Charis Eng
William D Foulkes, Jérôme Bertherat and Charis Eng
Lamis Yehia and Charis Eng
An average of 10% of all cancers (range 1–40%) are caused by heritable mutations and over the years have become powerful models for precision medicine practice. Furthermore, such cancer predisposition genes for seemingly rare syndromes have turned out to help explain mechanisms of sporadic carcinogenesis and often inform normal development. The tumor suppressor PTEN encodes a ubiquitously expressed phosphatase that counteracts the PI3K/AKT/mTOR cascade – one of the most critical growth-promoting signaling pathways. Clinically, individuals with germline PTEN mutations have diverse phenotypes and fall under the umbrella term PTEN hamartoma tumor syndrome (PHTS). PHTS encompasses four clinically distinct allelic overgrowth syndromes, namely Cowden, Bannayan-Riley-Ruvalcaba, Proteus and Proteus-like syndromes. Relatedly, mutations in other genes encoding components of the PI3K/AKT/mTOR pathway downstream of PTEN also predispose patients to partially overlapping clinical manifestations, with similar effects as PTEN malfunction. We refer to these syndromes as ‘PTEN-opathies.’ As a tumor suppressor and key regulator of normal development, PTEN dysfunction can cause a spectrum of phenotypes including benign overgrowths, malignancies, metabolic and neurodevelopmental disorders. Relevant to clinical practice, the identification of PTEN mutations in patients not only establishes a PHTS molecular diagnosis, but also informs on more accurate cancer risk assessment and medical management of those patients and affected family members. Importantly, timely diagnosis is key, as early recognition allows for preventative measures such as high-risk screening and surveillance even prior to cancer onset. This review highlights the translational impact that the discovery of PTEN has had on the diagnosis, management and treatment of PHTS.
Zi Ying Tan, Taosheng Huang and Joanne Ngeow
Hereditary cancer predisposition syndromes are associated with germline mutations that lead to increased vulnerability for an individual to develop cancers. Such germline mutations in tumour suppressor genes, oncogenes and genes encoding for proteins essential in DNA repair pathways and cell cycle control can cause overall chromosomal instability in the genome and increase risk in developing cancers. Gene correction of these germline mutations to restore normal protein functions is anticipated as a new therapeutic option. This can be achieved through disruption of gain-of-function pathogenic mutation, restoration of loss-of-function mutation, addition of a transgene essential for cell function and single nucleotide changes. Genome editing tools are applicable to precise gene correction. Development of genome editing tools comes in two waves. The first wave focuses on improving targeting specificity and editing efficiency of nucleases, and the second wave of gene editing draws on innovative engineering of fusion proteins combining deactivated nucleases and other enzymes that are able to create limitless functional molecular tools. This gene editing advancement is going to impact medicine, particularly in hereditary cancers. In this review, we discuss the application of gene editing as an early intervention and possible treatment for hereditary cancers, by highlighting a selection of highly penetrant cancer syndromes as examples of how this may be achieved in clinical practice.
Luis V Syro, Fabio Rotondo, Leon D Ortiz and Kalman Kovacs
Temozolomide is an alkylating chemotherapeutic agent used in malignant neuroendocrine neoplasia, melanoma, brain metastases and an essential component of adjuvant therapy in the treatment of glioblastoma multiforme and anaplastic astrocytoma. Since 2006, it has been used for the treatment of pituitary carcinomas and aggressive pituitary adenomas. Here, we discuss the current indications and results of temozolomide therapy in pituitary tumors, as well as frequently asked questions regarding temozolomide treatment, duration of therapy, dosage, tumor recurrence and resistance.
Chiara Verdelli, Irene Forno, Annamaria Morotti, Pasquale Creo, Vito Guarnieri, Alfredo Scillitani, Filomena Cetani, Leonardo Vicentini, Gianni Balza, Edoardo Beretta, Stefano Ferrero, Valentina Vaira and Sabrina Corbetta
Parathyroid tumors deregulate microRNAs belonging to the two clusters on the chromosome 19, the C19MC and miR-371-373 clusters. Here, we report that the embryonic miR-372 is aberrantly expressed in half of parathyroid adenomas (PAds) in most of atypical adenomas and carcinomas (n = 15). Through in situ hybridization, we identified that miR-372-positive parathyroid tumor cells were scattered throughout the tumor parenchyma. In PAd-derived cells, ectopic miR-372 inhibited the expression of its targets CDKN1A/p21 and LATS2 at both mRNA and protein levels. Although the viability of parathyroid cells was not affected by miR-372 overexpression, the miRNA blunted camptothecin-induced apoptosis in primary PAd-derived cultures. miR-372 overexpression in parathyroid tumor cells increased parathormone (PTH) mRNA levels, and it positively correlated in vivo with circulating PTH levels. Conversely, the parathyroid-specific genes TBX1 and GCM2 were not affected by miR-372 mimic transfection. Finally, miR-372 dampened the Wnt pathway in parathyroid tumor cells through DKK1 upregulation. In conclusion, miR-372 is a novel mechanism exploited by a subset of parathyroid tumor cells to partially decrease sensitivity to apoptosis, to increase PTH synthesis and to deregulate Wnt signaling.
J Crona, F Beuschlein, K Pacak and B Skogseid
This review aims to provide clinicians and researchers with a condensed update on the most important studies in the field during 2017. We present the academic output measured by active clinical trials and peer-reviewed published manuscripts. The most important and contributory manuscripts were summarized for each diagnostic entity, with a particular focus on manuscripts that describe translational research that have the potential to improve clinical care. Finally, we highlight the importance of collaborations in adrenal tumor research, which allowed for these recent advances and provide structures for future success in this scientific field.
Vanida A Serna, Xin Wu, Wenan Qiang, Justin Thomas, Michael L Blumenfeld and Takeshi Kurita
Cellular mechanisms of uterine leiomyoma (LM) formation have been studied primarily utilizing in vitro models. However, recent studies established that the cells growing in the primary cultures of MED12-mutant LM (MED12-LM) do not carry causal mutations. To improve the accuracy of LM research, we addressed the cellular mechanisms of LM growth and regression utilizing a patient-derived xenograft (PDX) model, which faithfully replicates the patient tumors in situ. The growth and maintenance of MED12-LMs depend on 17β-estradiol (E2) and progesterone (P4). We determined E2 and P4-activated MAPK and PI3K pathways in PDXs with upregulation of IGF1 and IGF2, suggesting that the hormone actions on MED12-LM are mediated by the IGF pathway. When hormones were removed, MED12-LM PDXs lost approximately 60% of volume within 3 days through reduction in cell size. However, in contrast to general belief, the survival of LM cells was independent of E2 and/or P4, and apoptosis was not involved in the tumor regression. Furthermore, it was postulated that abnormal collagen fibers promote the growth of LMs. However, collagen fibers of actively growing PDXs were well aligned. The disruption of collagen fibers, as found in human LM specimens, occurred only when the volume of PDXs had grown to over 20 times the volume of unstimulated PDXs, indicating disruption is the result of growth not the cause. Hence, this study revises generally accepted theories on the growth and regression of LMs.
Tom Lees, Angharad Cullinane, Alexandra Condon, Abeer M Shabaan, Matthew P Humphries and Valerie Speirs
Male breast cancer (MBC) incidence seems to parallel global increases in obesity. The stromal microenvironment contributes to carcinogenesis; yet, the role of adipocytes in this is understudied in MBC. We identified four cohorts of male breast tissues diagnosed when obesity was rare (archival cohort) and more common (contemporary cohort). We examined the microenvironment of archival and contemporary cohorts of MBC, diagnosed 1940–1970 and 1998–2006, respectively, with two cohorts of, archival and contemporary gynaecomastia, diagnosed 1940–1979 and 1996–2011, respectively, serving as controls. We quantified adipocytes, crown-like structures (CLS) and the presence of CD8, α smooth muscle actin (αSMA) and CD68+ macrophages in both cohorts, and determined how these affected survival, in the contemporary MBC cohort. In both MBC cohorts, mean adipocyte diameter was larger in the distant stroma compared with stroma close to the invading tumour (92.2 µm vs 66.7 µm). This was not seen in gynaecomastia. CLS were more frequent in both MBC cohorts than gynaecomastia (44/55 (80%) vs 11/18 (61%), P < 0.001). No relationship was found between CLS number and adipocyte size, although there were greater numbers of CLS in contemporary MBC > archival MBC > gynaecomastia. CD8 and CD68 expression in the stroma was significantly associated with reduced survival, with no effects seen with αSMA. Changes in the adipose-inflammatory microenvironment may be a contributing factor to the increase seen in MBC diagnosis.
Erin E Swinstead, Ville Paakinaho and Gordon L Hager
Reprogramming of the chromatin landscape is a critical component to the transcriptional response in breast cancer. Effects of sex hormones such as estrogens and progesterone have been well described to have a critical impact on breast cancer proliferation. However, the complex network of the chromatin landscape, enhancer regions and mode of function of steroid receptors (SRs) and other transcription factors (TFs), is an intricate web of signaling and functional processes that is still largely misunderstood at the mechanistic level. In this review, we describe what is currently known about the dynamic interplay between TFs with chromatin and the reprogramming of enhancer elements. Emphasis has been placed on characterizing the different modes of action of TFs in regulating enhancer activity, specifically, how different SRs target enhancer regions to reprogram chromatin in breast cancer cells. In addition, we discuss current techniques employed to study enhancer function at a genome-wide level. Further, we have noted recent advances in live cell imaging technology. These single-cell approaches enable the coupling of population-based assays with real-time studies to address many unsolved questions about SRs and chromatin dynamics in breast cancer.