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Mojun Zhu, Karl R Sorenson, Rebecca Liu, Bonnie E Gould Rothberg, and Thorvardur R Halfdanarson

Pancreatic neuroendocrine tumors (PNETs) encompass a diverse group of malignancies marked by histological heterogeneity and highly variable clinical outcomes. We performed a systematic review on potential prognostic biomarkers in PNETs by searching the PubMed database. A total of 472 manuscripts were reviewed in detail, of which 52 multivariate studies met the inclusion criteria proposed by the Reporting Recommendations for Tumor Marker Prognostic Studies. These altogether analyzed 53 unique targets, and 36 of them were statistically associated with survival.

Open access

Luise Eckardt, Maria Prange-Barczynska, Emma J Hodson, James W Fielding, Xiaotong Cheng, Joanna D C C Lima, Samvid Kurlekar, Gillian Douglas, Peter J Ratcliffe, and Tammie Bishop

Despite a general role for the HIF hydroxylase system in cellular oxygen sensing and tumour hypoxia, cancer-associated mutations of genes in this pathway, including PHD2, PHD1, EPAS1 (encoding HIF-2α) are highly tissue-restricted, being observed in pseudohypoxic pheochromocytoma and paraganglioma (PPGL) but rarely, if ever, in other tumours. In an effort to understand that paradox and gain insights into the pathogenesis of pseudohypoxic PPGL, we constructed mice in which the principal HIF prolyl hydroxylase, Phd2, is inactivated in the adrenal medulla using TH-restricted Cre recombinase. Investigation of these animals revealed a gene expression pattern closely mimicking that of pseudohypoxic PPGL. Spatially resolved analyses demonstrated a binary distribution of two contrasting patterns of gene expression among adrenal medullary cells. Phd2 inactivation resulted in a marked shift in this distribution towards a Pnmt /Hif-2α +/Rgs5 + population. This was associated with morphological abnormalities of adrenal development, including ectopic TH+ cells within the adrenal cortex and external to the adrenal gland. These changes were ablated by combined inactivation of Phd2 with Hif-2α, but not Hif-1α. However, they could not be reproduced by inactivation of Phd2 in adult life, suggesting that they arise from dysregulation of this pathway during adrenal development. Together with the clinical observation that pseudohypoxic PPGL manifests remarkably high heritability, our findings suggest that this type of tumour likely arises from dysregulation of a tissue-restricted action of the PHD2/HIF-2α pathway affecting adrenal development in early life and provides a model for the study of the relevant processes.

Free access

James F H Pittaway, Constantinos Lipsos, Katia Mariniello, and Leonardo Guasti

Delta-like non-canonical Notch ligand 1 (DLK1) is a cleavable single-pass transmembrane protein and a member of the Notch/Delta/Serrate family. It is paternally expressed and belongs to a group of imprinted genes located on chromosome band 14q32 in humans and 12qF1 in mice. DLK1 is expressed in many human tissues during embryonic development but in adults expression is low and is mostly restricted to (neuro)endocrine tissues and other immature stem/progenitor cells (notably hepatoblasts). However, DLK1 is expressed at a high frequency in many common malignancies (liver, breast, brain, pancreas, colon and lung). More recently, high levels of expression have been identified in endocrine-related cancers such as ovarian and adrenocortical carcinoma. There is growing evidence that DLK1 expression in cancer is associated with worse prognosis and that DLK1 may be a marker of cancer stem cells. Although the exact mechanism through which DLK1 functions is not fully understood, it is known to maintain cells in an undifferentiated phenotype and has oncogenic properties. These effects are partly exacted through interaction with the Notch signalling pathway. In this review, we have detailed the functional role of DLK1 within physiology and malignancy and posited a mechanism for how it exacts its oncogenic effects. In describing the expression of DLK1 in cancer and in healthy tissue, we have highlighted the potential for its use both as a biomarker and as a potential therapeutic target.

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Arianna Ventura-Bahena, Jesús Gibran Hernández-Pérez, Luisa Torres-Sánchez, Adolfo Sierra-Santoyo, Derly Constanza Escobar-Wilches, Consuelo Escamilla-Núñez, Rocio Gómez, Francisco Rodríguez-Covarrubias, Ma. de Lourdes López-González, and Mario Figueroa

Epidemiological studies related to androgens and prostate cancer (PC) have focused on serum determination of testosterone, androstenedione (A4), and DHEA, with inconsistent results. Herein, we hypothesized that differences in androgen biosynthetic and metabolic pathways, rather than differences in specific androgen concentrations, are associated with prostatic carcinogenesis. Therefore, spot urine samples from 111 incident PC cases with Gleason score at diagnosis and 227 healthy population controls, were analyzed. Urinary androgen concentrations (nanograms/milligrams of creatinine) were determined by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS). Using a factor analysis, we identified three androgen urinary excretion patterns. In a subsample, we evaluated a modification effect of the androgen receptor (AR) CAG polymorphism. Pattern I, characterized by A4 and testosterone hydroxylated metabolites (11β-OHT; 2β-OHT; 15β-OHT; 2α-OHT; 6β-OHT), was associated with high PC odds among carriers of AR gene (CAG)>19 repeats (OR: 3.67 95% CI: 1.23–11.0; P for interaction= 0.009). Conversely, higher testosterone excretion (pattern III), was marginally associated with lower (OR: 0.35 95% CI: 0.12–1.00, P for trend= 0.08) poorly differentiated PC (Gleason ≥8). No clear association was observed with pattern II (DHEA; 16α and 16β-OHT). Our results were consistent with the previous evidence which suggests that the C11-oxy backdoor pathway is important for prostatic carcinogenesis. Androgen urine excretion analysis could be useful for PC diagnosis, treatment, and prognosis; however, further studies with a larger number of samples and the urinary determination of 11-ketoandrogens are necessary.

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Thalles Fernando Rocha Ruiz, Simone J Colleta, Ellen C R Leonel, and Sebastião Roberto Taboga

Compounds that trigger breast cancer onset and establishment are of great interest in biological research. Endocrine disruptors are relevant because they initiate carcinogenesis by changing endocrine pathways. Bisphenol A (BPA), as a ubiquitous xenoestrogen, is largely associated with dysfunctions in the female reproductive system and associated organs. This study proposes an investigation of the mammary gland (MG) in aged Mongolian gerbil (Meriones unguiculatus) mothers after their exposure to BPA in two windows of morphophysiological plasticity: pregnancy and lactation. A low dose (50 μg/kg) and a high dose (5000 μg/kg) of BPA were considered, and results showed few differences between them. As expected, we observed contrasts among control and BPA-exposed MG. The control groups presented a regressive phase with high apoptotic activity and elastic stroma. However, BPA damaged mammary tissue and provoked multifocal carcinoma development supported by an apparent epithelial-mesenchymal transition (EMT) and reactive stroma establishment. BPA remodeled stromal fibers deposition and enhanced the recruitment of tumor-associated cells, contributing to a tumoral microenvironment. Overexpression of TGF-β1 was induced by BPA in the epithelial compartment of exposed MG, and increased expression of metalloproteinases (MMP-2, MMP-3, MMP-9) was present in carcinoma cells. In conclusion, exposure of mothers to BPA during the gestational/lactational window of susceptibility leads to carcinogenic impacts with aging.

Free access

Hany Sadek Ayoub Ghaly and Pegah Varamini

Cancer is the uncontrolled division of abnormal cells in a specific organ. Globally, about one in six deaths is due to cancer. Despite the plethora of research being undertaken worldwide to find a cure for cancer, it remains a significant challenge. Cancer targeting via agents designed to interfere with some specifically or highly expressed molecules in cancer cells has been a shift in the treatment of various forms of cancers. The development of drug delivery systems, specifically to cancer cells, is a common approach that succeeded in increasing the efficacy and reducing the side effects of different anticancer agents. Gonadotropin-releasing hormone (GnRH) is a naturally occurring hormone with receptors overexpressed in many types of cancers related or unrelated to the reproductive system. Several drug delivery systems were developed using GnRH derivatives as targeting agents. In this review, we first discuss the role of GnRH and its receptors in cancer. Then, we provide a detailed insight into different delivery systems developed using GnRH derivatives as targeting agents in various types of GnRH receptor overexpressing cancers. Some promising findings from these studies indicate that GnRH receptor targeting is a potential strategy to efficiently guide anticancer therapeutics, diagnostic agents, and nucleic acids directly to cancer cells. Lastly, some limitations of the current research and suggestions for more successful outcomes in clinical trials of these delivery systems are highlighted.

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Karel Pacak, Mark Kidd, Leah Meuter, and Irvin M Modlin

Pheochromocytomas and paragangliomas (PHEOs/PGLs) represent diagnostically challenging and complex neuroendocrine tumors (NETs). Current biomarker tests for PHEOs/PGLs are technically complex or limited. We assessed the diagnostic utility of a NET-specific 51-marker gene blood assay (NETest) in patients with PHEOs/PGLs (n = 81), including ten pediatric patients, and age-/gender-matched controls (n = 142) using a prospective case:control (1:2) analysis. mRNA was measured (qPCR), and results were scaled from 0 to 100 (upper limit of normal < 20). Receiver operating curve (ROC) and non-parametric (Mann–Whitney) tests were used for analyses (two-tailed). All data are presented as mean ± s.e.m. NETest accuracy for PHEO/PGL diagnosis was 100%. PHEO/PGL scores were 70 ± 3 vs 8.5 ± 1 in controls (P < 0.0001), and ROC analysis was 0.99 ± 0.004 (P < 0.0001). Diagnostic metrics were 94% accurate, 100% sensitive, and 92% specific. Imaging correlation with 68Ga-PET-SSA was 100%. NETest levels in PHEOs (n = 26) were significantly (P < 0.0001) elevated (83 ± 4) vs 66 ± 4 in PGLs (n = 40) and mixed PHEOs/PGLs (n = 5: 37 ± 3). Adrenal-derived tumors (n = 30) exhibited higher scores (76 ± 5) than extra-adrenal-derived tumors (66 ± 4, P < 0.05). Cluster 2 tumors exhibited significantly (P = 0.034) elevated NETest levels (n = 4: 92 ± 2) vs cluster 1 tumors (n = 35: 69 ± 4). Regulatory pathway analysis identified elevated RAS-RAF, metastatic, pluripotential, neural and secretory gene cluster levels (P < 0.05) in PHEOs compared to PGLs. Cluster 2 PPGLs exhibited elevated (P = 0.046) levels of growth factor signaling genes compared to cluster 1. The PHEOs/PGLs in the pediatric cohort (n = 10) were all NETest-positive (81 ± 8) and exhibited a gene expression profile spectrum analogous to adults. Circulating NET transcript analysis identifies PHEOs/PGLs with 100% efficacy and is likely to have clinical utility in the diagnosis and management of PHEO/PGL patients.

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Eilon Krashin, Barbara Silverman, David M Steinberg, Daniel Yekutieli, Shmuel Giveon, Offer Fabian, Aleck Hercbergs, Paul J Davis, Martin Ellis, and Osnat Ashur-Fabian

Research on the association between thyroid hormone levels and cancer mortality remains limited and inconclusive. We determined the relation of thyroid stimulating hormone (TSH), free T4 (FT4), and free T3 (FT3) levels with mortality in overall cancer and specific tumor types. Thyroid hormone levels 1–5 years prior to cancer diagnosis, as well as multiple clinical and demographic parameters, were retrospectively collected for 10,325 Israeli cancer patients, diagnosed between 2000 and 2016. Patients treated with thyroid altering medications were excluded. Cancer diagnosis was determined via the Israel National Cancer Registry. Multivariate-adjusted Cox proportional hazards model was used to assess the hazard ratios (HRs) based on thyroid hormone function for cancer mortality. A total of 5265 patients died during the follow-up period (median of 4.4 years). TSH, FT4, and FT3 levels in the hypothyroid range were associated with increase in overall mortality (adjusted HR 1.20, 1.74, 1.87, respectively). We further analyzed the association between TSH and mortality in 14 cancer subgroups. Specifically, TSH in both the hyperthyroid and hypothyroid range was associated with melanoma mortality (adjusted HR 2.20, 4.47, respectively). In conclusion, pre-diagnosis of thyroid dysfunction is associated with increased cancer mortality, a relation likely driven by specific cancer types. These findings suggest that thyroid hormones may potentially serve as prognostic markers in cancer.

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Marta Araujo-Castro, Rogelio Garcia Centeno, María-Carmen López-García, Cristina Lamas, Cristina Álvarez-Escolá, María Calatayud Gutiérrez, Concepción Blanco-Carrera, Paz de Miguel Novoa, Nuria Valdés, Paola Gracia Gimeno, Mariana Tomé Fernández-Ladreda, César Mínguez Ojeda, Juan Carlos Percovich Hualpa, Mireia Mora, Óscar Vidal, Ana Serrano Romero, Felicia Alexandra Hanzu, and Victoria Gómez Dos Santos

We aimed to identify presurgical and surgical risk factors for intraoperative complications in patients with pheochromocytomas. A retrospective study of patients with pheochromocytomas who underwent surgery in ten Spanish hospitals between 2011 and 2021 was performed. One hundred and sixty-two surgeries performed in 159 patients were included. The mean age was 51.6 ± 16.4 years old and 52.8% were women. Median tumour size was 40 mm (range 10–110). Laparoscopic adrenalectomy was performed in 148 patients and open adrenalectomy in 14 patients. Presurgical alpha- and beta-blockade was performed in 95.1% and 51.9% of the surgeries, respectively. 33.3% of the patients (n = 54) had one or more intraoperative complications. The most common complication was the hypertensive crisis in 21.0%, followed by prolonged hypotension in 20.0%, and hemodynamic instability in 10.5%. Patients pre-treated with doxazosin required intraoperative hypotensive treatment more commonly than patients pre-treated with other antihypertensive drugs (51.1% vs 26.5%, P = 0.002). Intraoperative complications were more common in patients with higher levels of urine metanephrine (OR = 1.01 for each 100 μg/24 h, P = 0.026) and normetanephrine (OR = 1.00 for each 100 μg/24 h, P = 0.025), larger tumours (OR = 1.4 for each 10 mm, P < 0.001), presurgical blood pressure > 130/80 mmHg (OR = 2.25, P = 0.027), pre-treated with doxazosin (OR = 2.20, P = 0.023) and who had not received perioperative hydrocortisone (OR = 3.95, P = 0.008). In conclusion, intraoperative complications in pheochromocytoma surgery are common and can be potentially life-threatening. Higher metanephrine and normetanephrine levels, larger tumour size, insufficient blood pressure control before surgery, pre-treatment with doxazosin, and the lack of treatment with perioperative hydrocortisone are associated with higher risk of intraoperative complications.

Open access

Adel Mandl, James M Welch, Gayathri Kapoor, Vaishali I Parekh, David S Schrump, R Taylor Ripley, Mary F Walter, Jaydira Del Rivero, Smita Jha, William F Simonds, Robert T Jensen, Lee S Weinstein, Jenny E Blau, and Sunita K Agarwal

Patients with the multiple endocrine neoplasia type 1 (MEN1) syndrome carry germline heterozygous loss-of-function mutations in the MEN1 gene which predisposes them to develop various endocrine and non-endocrine tumors. Over 90% of the tumors show loss of heterozygosity (LOH) at chromosome 11q13, the MEN1 locus, due to somatic loss of the wild-type MEN1 allele. Thymic neuroendocrine tumors (NETs) or thymic carcinoids are uncommon in MEN1 patients but are a major cause of mortality. LOH at the MEN1 locus has not been demonstrated in thymic tumors. The goal of this study was to investigate the molecular aspects of MEN1-associated thymic tumors including LOH at the MEN1 locus and RNA-sequencing (RNA-Seq) to identify genes associated with tumor development and potential targeted therapy. A retrospective chart review of 294 patients with MEN1 germline mutations identified 14 patients (4.8%) with thymic tumors (12 thymic NETs and 2 thymomas). LOH at the MEN1 locus was identified in 10 tumors including the 2 thymomas, demonstrating that somatic LOH at the MEN1 locus is also the mechanism for thymic tumor development. Unsupervised principal component analysis and hierarchical clustering of RNA-Seq data showed that thymic NETs formed a homogenous transcriptomic group separate from thymoma and normal thymus. KSR2 (kinase suppressor of Ras 2), that promotes Ras-mediated signaling, was abundantly expressed in thymic NETs, a potential therapeutic target. The molecular insights gained from our study about thymic tumors combined with similar data from other MEN1-associated tumors may lead to better surveillance and treatment of these rare tumors.