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Open access

K G Samsom, L M van Veenendaal, G D Valk, M R Vriens, M E T Tesselaar and J G van den Berg

Background

Small-intestinal neuroendocrine tumours (SI-NETs) represent a heterogeneous group of rare tumours. In recent years, basic research in SI-NETs has attempted to unravel the molecular events underlying SI-NET tumorigenesis.

Aim

We aim to provide an overview of the current literature regarding prognostic and predictive molecular factors in patients with SI-NETs.

Method

A PubMed search was conducted on (epi)genetic prognostic factors in SI-NETs from 2000 until 2019.

Results

The search yielded 1522 articles of which 20 reviews and 35 original studies were selected for further evaluation. SI-NETs are mutationally quiet tumours with a different genetic make-up compared to pancreatic NETs. Loss of heterozygosity at chromosome 18 is the most frequent genomic aberration (44–100%) followed by mutations of CDKN1B in 8%. Prognostic analyses were performed in 16 studies, of which 8 found a significant (epi)genetic association for survival or progression. Loss of heterozygosity at chromosome 18, gains of chromosome 4, 5, 7, 14 and 20p, copy gain of the SRC gene and low expression of RASSF1A and P16 were associated with poorer survival. In comparison with genetic mutations, epigenetic alterations are significantly more common in SI-NETs and may represent more promising targets in the treatment of SI-NETs.

Conclusion

SI-NETs are mutationally silent tumours. No biomarkers have been identified yet that can easily be adopted into current clinical decision making. SI-NETs may represent a heterogeneous disease and larger international studies are warranted to translate molecular findings into precision oncology.

Open access

Lesley Hill, Zeynep Sumer-Bayraktar, John G Lewis, Eva Morava, Morten Thaysen-Andersen and Geoffrey L Hammond

Objective: Discrepancies in enzyme-linked immunosorbent assay (ELISA) measurements of human corticosteroid-binding globulin (CBG) using detection monoclonal antibodies that recognize an epitope (9G12) within its reactive center loop (RCL), versus an epitope (12G2) in a different location, have suggested that CBG with a proteolytically-cleaved RCL exists in blood samples. We have previously been unable to verify this biochemically, and sought to determine if N-glycosylation differences account for discrepancies in ELISA measurements of CBG.

Methods and Subjects: Molecular biological, biochemical and glycopeptide analyses were used to examine how N-glycosylation at specific sites, including at N347 within the RCL, affect CBG ELISA or steroid-binding capacity assay (BCA) measurements. Plasma from patients with congenital disorders of glycosylation (CDG) was also examined in these assays as examples of N-glycosylation defects.

Results: We demonstrate that an N-glycan at N347 within the CBG RCL limits the 9G12 antibody from recognising its epitope, whereas the 12G2 antibody reactivity is unaffected, thereby contributing to discrepancies in ELISA measurements using these two antibodies. Qualitative differences in N-glycosylation at N238 also negatively affect the steroid-binding of CBG in the absence of an N-glycan at N347 caused by a T349A substitution. Desialylation increased both ELISA measurements relative to BCA values. Similarly, plasma CBG levels in both ELISAs were much higher than BCA values in several CDG patients.

Conclusions: Plasma CBG measurements are influenced by variations in N-glycosylation. This is important given the increasing number of CDG defects identified recently, and because N-glycosylation abnormalities are common in patients with metabolic and liver diseases.

Open access

Gaëtan Prévost, Marie Picot, Marie-Anne Le Solliec, Arnaud Arabo, Hind Berrahmoune, Mouna El Mehdi, Saloua Cherifi, Alexandre Benani, Emmanuelle Nédélec, Françoise Gobet, Valéry Brunel, Jérôme Leprince, Hervé Lefebvre, Youssef Anouar and Nicolas Chartrel

Objective

Recent studies performed in mice revealed that the neuropeptide 26RFa regulates glucose homeostasis by acting as an incretin and by increasing insulin sensitivity. However, in humans, an association between 26RFa and the regulation of glucose homeostasis is poorly documented. In this study, we have thus investigated in detail the distribution of 26RFa and its receptor, GPR103, in the gut and the pancreas, and determined the response of this peptidergic system to an oral glucose challenge in obese patients.

Design and methods

Distribution of 26RFa and GPR103 was examined by immunohistochemistry using gut and pancreas tissue sections. Circulating 26RFa was determined using a specific radioimmunoassay in plasma samples collected during an oral glucose tolerance test.

Results

26RFa and GPR103 are present all along the gut but are more abundant in the stomach and duodenum. In the stomach, the peptide and its receptor are highly expressed in the gastric glands, whereas in the duodenum, ileum and colon they are present in the enterocytes and the goblet cells. In the pancreatic islets, the 26RFa/GPR103 system is mostly present in the β cells. During an oral glucose tolerance test, plasma 26RFa profile is different between obese patients and healthy volunteers, and we found strong positive correlations between 26RFa blood levels and the BMI, and with various parameters of insulin secretion and insulin resistance.

Conclusion

The present data suggest an involvement of the 26RFa/GPR103 peptidergic system in the control of human glucose homeostasis.

Open access

Tiina Vesterinen, Teijo Kuopio, Maarit Ahtiainen, Aija Knuuttila, Harri Mustonen, Kaisa Salmenkivi, Johanna Arola and Caj Haglund

Pulmonary carcinoid (PC) tumors are rare tumors that account for approximately 1% of all lung cancers. The primary treatment option is surgery, while there is no standard treatment for metastatic disease. As the number of PCs diagnosed yearly is increasing, there is a need to establish novel therapeutic options. This study aimed to investigate programmed death protein 1 (PD-1) and programmed death ligand 1 (PD-L1) expression in PC tumors since blocking of the PD-1/PD-L1 pathway is a promising therapeutic option in various other malignancies. A total of 168 PC patients treated between 1990 and 2013 were collected from the Finnish biobanks. After re-evaluation of the tumors, 131 (78%) were classified as typical carcinoid (TC) and 37 (22%) as atypical carcinoid (AC) tumors. Primary tumor samples were immunohistochemically labeled for PD-1, PD-L1, and CD8. High PD-1 expression was detected in 16% of the tumors. PD-L1 expression was detected in 7% of TC tumors; all AC tumors were PD-L1 negative. PD-L1 expression was associated with mediastinal lymph-node metastasis at the time of diagnosis (P=0.021) as well as overall metastatic potential of the tumor (P=0.010). Neither PD-1 expression, PD-L1 expression nor CD8+ T cell density was associated with survival. In conclusion, PD-1 and PD-L1 were expressed in a small proportion of PC tumors and PD-L1 expression was associated with metastatic disease. Targeting of the PD-1/PD-L1 pathway with immune checkpoint inhibitors may thus offer a treatment option for a subset of PC patients.

Open access

Eva Jakobsson Ung, Ann-Charlotte Olofsson, Ida Björkman, Tobias Hallén, Daniel S Olsson, Oskar Ragnarsson, Thomas Skoglund, Sofie Jakobsson and Gudmundur Johannsson

Objective

Experiences and need of support during surgery and start of replacement therapy in patients with pituitary tumours are highly unknown. This study aimed at exploring patient experiences during pre- and postoperative care and recovery after pituitary surgery in patients with a pituitary tumour.

Methods

Within a qualitative study design, 16 consecutive patients who underwent surgery for pituitary tumours were repeatedly interviewed. In total, 42 interviews were performed before and after surgery. Analysis was performed using qualitative interpretation.

Results

Suffering a pituitary tumour was overwhelming for many patients and struggling with existential issues was common. Patients expressed loneliness and vulnerability before and after surgery. How professionals handled information in connection with diagnosis greatly affected the patients. Other patients with the same diagnosis were experienced as the greatest support. Normalisation of bodily symptoms and relationships with others were reported during postoperative recovery. However, a fear that the tumour would return was present.

Conclusions

Patients with pituitary tumours need structured support, including peer support, which acknowledges physical, cognitive as well as emotional and existential concerns. Information related to diagnosis and surgery should be adapted in relation to the loneliness and the existential seriousness of the situation. Care and support for patients with pituitary tumours should preferably be organised based on continuity and an unbroken care pathway from the first pre-operative evaluation through to postoperative care and the start of a life-long endocrine treatment and tumour surveillance.

Open access

Marloes Emous, Merel van den Broek, Ragnhild B Wijma, Loek J M de Heide, Gertjan van Dijk, Anke Laskewitz, Erik Totté, Bruce H R Wolffenbuttel and André P van Beek

Objective

Roux-en-Y gastric bypass (RYGB) is an effective way to induce sustainable weight loss and can be complicated by postprandial hyperinsulinaemic hypoglycaemia (PHH). To study the prevalence and the mechanisms behind the occurrence of hypoglycaemia after a mixed meal tolerance test (MMTT) in patients with primary RYGB.

Design

This is a cross-sectional study of patients 4 years after primary RYGB.

Methods

From a total population of 550 patients, a random sample of 44 patients completed the total test procedures. A standardized mixed meal was used as stimulus. Venous blood samples were collected at baseline, every 10 min during the first half hour and every 30 min until 210 min after the start. Symptoms were assessed by questionnaires. Hypoglycaemia is defined as a blood glucose level below 3.3 mmol/L.

Results

The prevalence of postprandial hypoglycaemia was 48% and was asymptomatic in all patients. Development of hypoglycaemia was more frequent in patients with lower weight at surgery (P = 0.045), with higher weight loss after surgery (P = 0.011), and with higher insulin sensitivity calculated by the homeostasis model assessment indexes (HOMA2-IR, P = 0.014) and enhanced beta cell function (insulinogenic index at 20 min, P = 0.001).

Conclusion

In a randomly selected population 4 years after primary RYGB surgery, 48% of patients developed a hypoglycaemic event during an MMTT without symptoms, suggesting the presence of hypoglycaemia unawareness in these patients. The findings in this study suggest that the pathophysiology of PHH is multifactorial.

Open access

Boju Pan, Anqi Wang, Junyi Pang, Yuhan Zhang, Ming Cui, Jian Sun and Zhiyong Liang

Introduction

PD-L1 is associated with prognosis and immunotherapeutic response in patients with malignancies. In previous studies, PD-L1 expression was detected in many endocrine tumors. However, the PD-L1 expression status in parathyroid tumors is unknown.

Methods

We included 26 parathyroid carcinoma and 37 adenoma samples, as well as the corresponding patient information. PD-L1 was stained using the FDA-approved PD-L1 IHC 22C3 pharmDx and Ventana PD-L1 (SP263) assays, and staining was assessed by the estimated percentages of positive tumor cells and immune cells, respectively.

Results

We classified the PD-L1 expression in the parathyroid tumors into four groups: (0) <1%, (1) 1–4%, (2) 5–9% and (3) ≥10% positive. With the SP263 clone, 37 (carcinoma:adenoma = 18:19) samples scored 0, 13 (carcinoma:adenoma = 4:9) scored 1, 7 (carcinoma:adenoma = 1:6) scored 2 and 6 (carcinoma:adenoma = 3:3) scored 3. However, in the series of cases using the 22C3 clone, 45 (carcinoma:adenoma = 20:25) samples scored 0, 10 (carcinoma: adenoma = 3:7) scored 1, 5 (carcinoma:adenoma = 1:4) scored 2, and 3 (carcinoma:adenoma = 2:1) scored 3. Concerning tumor-infiltrating immune cells, 57 samples were negative and six were positive with SP263, and 59 were negative and four were positive with 22C3. Moreover, PD-L1 expression was negatively correlated with the Ki-67 index and mitotic rate in parathyroid tumors depending on the different clones. However, the results indicated only moderate consistency between the SP263 and 22C3 clones in parathyroid tumors.

Conclusion

We found deficient PD-L1 expression in the majority of parathyroid tumors. However, the PD-L1 expression score in parathyroid tumors depended greatly on the antibody clone used.

Open access

Chan Sub Park, Jihye Choi, Min-Ki Seong, Sung-Eun Hong, Jae-Sung Kim, In-Chul Park, Hyesil Seol, Woo Chul Noh and Hyun-Ah Kim

Estradiol is a key factor for tumorigenesis and prognosis of hormone receptor-positive breast cancer. Adipocytes are one source of estradiol in patients with breast cancer. Recent studies have shown that phosphorylated ribosomal protein S6 kinase-1 plays a critical role in adipogenesis. Therefore, estrogen depletion therapy might have beneficial effects in phosphorylated ribosomal protein S6 kinase-1-positive breast cancer. This study was conducted to evaluate the value of phosphorylated ribosomal protein S6 kinase-1 as a marker for gonadotropin-releasing hormone agonist treatment, a form of estrogen depletion therapy, for premenopausal patients with HR-positive, human epidermal growth factor receptor 2-negative breast cancer. We reviewed the medical records of 296 premenopausal patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative primary invasive breast cancer treated between 2008 and 2015. Phosphorylated ribosomal protein S6 kinase-1 positivity was defined by immunohistochemical staining scores of 1+, 2+ and 3+, whereas a score of 0 was considered negative. Phosphorylated ribosomal protein S6 kinase-1-positive tumors were found in 74.0% of the patients. In the phosphorylated ribosomal protein S6 kinase-1-positive group, disease-free survival of patients treated with a gonadotropin-releasing hormone agonist was significantly longer than that of patients treated without a gonadotropin-releasing hormone agonist (mean 106.7 months vs mean 91.1 months, P = 0.018). Phosphorylated ribosomal protein S6 kinase-1 is a potential biomarker for predicting the efficacy of gonadotropin-releasing hormone agonist therapy in premenopausal patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer.

Open access

Elham Barazeghi, Per Hellman, Gunnar Westin and Peter Stalberg

Small intestinal neuroendocrine tumors (SI-NETs) are small, slow growing neoplasms with loss of one copy of chromosome 18 as a common event. Frequently mutated genes on chromosome 18 or elsewhere have not been found so far. The aim of this study was to investigate a possible tumor suppressor role of the transmembrane receptor type tyrosine phosphatase PTPµ (PTPRM at 18p11) in SI-NETs. Immunohistochemistry, quantitative RT-PCR, colony formation assay, and quantitative CpG methylation analysis by pyrosequencing were performed. Undetectable/very low levels of PTPRM or aberrant pattern of immunostaining, with both negative and positive areas, were detected in the majority of tumors (33/40), and a significantly reduced mRNA expression in metastases compared to primary tumors was observed. Both the DNA methylation inhibitor 5-aza-2′-deoxycytidine and the S-adenosylhomocysteine hydrolase inhibitor 3-deazaneplanocin A (DZNep) induced PTPRM expression in CNDT2.5 and KRJ-I SI-NET cells. CpG methylation of upstream regulatory regions, the promoter region, and the exon 1/intron 1 boundary was detected by pyrosequencing analysis of the two cell lines and not in the analyzed SI-NETs. Overexpression of PTPRM in the SI-NET cell lines reduced cell growth and cell proliferation, and induced apoptosis. The tyrosine phosphatase activity of PTPRM was not involved in cell growth inhibition. The results support a role for PTPRM as a dysregulated candidate tumor suppressor gene in SI-NETs and further analyses of the involved mechanisms are warranted.

Open access

Manjunath Goroshi, Swati S Jadhav, Vijaya Sarathi, Anurag R Lila, Virendra A Patil, Ravikumar Shah, Priya Hira, Rajaram Sharma, Shettepppa Goroshi, Gwendolyn Fernandes, Amey Rojekar, Abhay Dalvi, Ganesh Bakshi, Gagan Prakash, Nalini S Shah and Tushar R Bandgar

Rationale and introduction

To evaluate the computerised tomography (CT) characteristics of phaeochromocytoma (PCC) that differentiate them from other non-benign adrenal masses such as adrenocortical carcinoma (ACC), primary adrenal lymphoma (PAL) and adrenal metastases (AM).

Methods

This retrospective study was conducted at a tertiary health care institute from Western India. Patients presented between January 2013 and August 2016 with histological diagnosis of PCC or other non-benign adrenal mass having adequate reviewable imaging data comprising all four CECT phases were included.

Results

The study cohort consisted of 72 adrenal masses from 66 patients (33 PCC, 22 ACC, 4 PAL, 13 AM). Unlike other masses, majority of PCC (25/33) showed peak enhancement in early arterial phase (EAP). PCC had significantly higher attenuation in EAP and early venous phase (EVP), and higher calculated percentage arterial enhancement (PAE) and percentage venous enhancement (PVE) than other adrenal masses (P < 0.001). For diagnosis of PCC with 100% specificity, PAE value ≥100% and EAP attenuation ≥100 HU had 78.8 and 63.6% sensitivity respectively. ACC were significantly larger in size as compared to PCC and metastasis. The adreniform shape was exclusively found in PAL (two out of four) and AM (4 out of 13). None of the enhancement, wash-in or washout characteristics were discriminatory among ACC, PAL and AM.

Conclusion

Peak enhancement in EAP, PAE value ≥100% and EAP attenuation ≥100 HU differentiate PCC from other malignant adrenal masses with high specificity.