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Background/aims: Lung carcinoids are uncommon neuroendocrine tumours. Molecular features of lung carcinoids have been poorly defined. microRNAs (miRNAs) are potent gene expression regulators with important roles in cancer development and progression. However, little is known on the role of miRNAs in the pathogenesis of lung carcinoids. Our goals were to identify commonly deregulated miRNAs in a rare case of lung carcinoid of typical histology with metastasis, as well as map miRNA target genes in pathways potentially associated with disease development and progression., Methods: miRNA expression profiles were assessed using the TaqMan Low Density Arrays, which is a platform including 384 miRNAs. miRNA profiles were generated in the tumor and its corresponding lymph node metastasis, compared to reference normal lung tissues. Furthermore, miRNA expression was validated in a separate, publicly available external dataset (n=19 typical lung carcinoids; 2/19 were metastatic tumors, compared to six normal lung tissues, GSE77380). Following this analysis, computational tools were applied for data interpretation. miRTarBase was used to determine miRNA-target genes, followed by ToppGene Suite analysis to identify pathways and biological functions. In addition, the expression of genes targeted by miRNAs was validated in a second, separate external dataset (n=13 tumour samples, GSE35679). GEO2R data analysis tool was used in both validation analyses (miRNAs and genes)., Results: We identified 15 commonly significantly downregulated miRNAs (fold change, FC≥2 and p<0.05) in the tumour and its paired metastasis, with further decreasing levels in the metastatic lesion. Downregulation of miR-126-3p and miR-146b-5p was validated in the external dataset GSE77380. In addition, SOX2 and TCF4 genes, targeted by miR-126-3p, were consistently overexpressed in a subset of six typical lung carcinoids from the external dataset GSE35679. Pathways analysis showed that miRNAs miR-126-3p and miR-146b-5p target genes with a role in the regulation of adaptive immune response., Conclusion: Our results contribute to the identification of miRNA expression changes in a typical lung carcinoid and its corresponding lymph node metastasis. Down-regulated levels of miR-126-3p and miR-146b-5p and target gene over-expression could play a role in the progression of this case of primary typical lung carcinoid to regional metastasis. Identified miRNAs and target genes are potential candidates for validation in a larger number of cases., Competing Interests: The authors have no conflicts of interest to declare., (© Copyright by the Author(s). Published by Cell Physiol Biochem Press.)

Pulmonary typical carcinoid (TC) is a low-grade, rare lung cancer of neuroendocrine origin. Currently, there is very little information available about the immune cell composition in TC tumours. Here, we analysed by flow cytometry resected tumours from four never-smoker female patients with TC. Twelve distinct immune cell types were identified in TC tumours. The most abundant immune cells were CD8 + T cells, CD4 + T cells, B cells and macrophages, which represented 19.8%, 17.7%, 11.5% and 11% of all tumour-infiltrating CD45 + leucocytes, respectively. Natural killer (NK) cells (8.8%) and neutrophils (3.9%) were also common. Three types of dendritic cells (DCs) were identified (plasmacytoid DCs, CD1c  DCs, and CD141  DCs) which together constituted 1.4% of all immune cells in TC tumours. Small populations of basophils (1.2%), mast cells (0.8%) and eosinophils (0.6%) were also present. Notably, the percentage of leucocytes (of all living cells) was much lower in TC tumours compared to high-grade non-small cell lung cancer (NSCLC) tumours and also compared to non-cancerous lung tissue. We conclude that TC tumours are relatively non-inflammatory, although the immune landscape was found to be very complex., (© 2020 The Authors. Scandinavian Journal of Immunology published by John Wiley & Sons Ltd on behalf of The Scandinavian Foundation for Immunology.)

The pathological features of the appendix tumors fundamentally recall those of the more frequent colorectal neoplasms, although with a higher relative incidence of carcinoids, due to the abundant presence of enteroendocrine cells in the appendix wall. Moreover, different types of lymphomas, Hodgkin and non-Hodgkin, arising from the extra-nodal mucosal-associated lymphatic tissue, can be encountered. The appendix tumor microenvironment (TME) consists of a cellular component and of a noncellular component: the former includes the immunocompetent cells, while the latter represents the support stroma. Particularly in carcinoids, the immune cell reaction can be explicated by tumor-infiltrating lymphocytes, which, in some circumstances, may arrange around and inside the tumor in a brisk fashion influencing favorably the prognosis. This active reaction has to be distinguished from any preexisting inflammatory condition of the appendix and from superimposed tumor complications, such as infection or ischemia. In practice, we consider the appendix TME a complex framework with immunological, mechanic, and metabolic functions, all supported by a marked neo-lymphoangiogenesis.

Background: Sunitinib is approved worldwide for treatment of advanced pancreatic neuroendocrine tumours (pNET), but no validated markers exist to predict response. This analysis explored biomarkers associated with sunitinib activity and clinical benefit in patients with pNET and carcinoid tumours in a phase II study., Methods: Plasma was assessed for vascular endothelial growth factor (VEGF)-A, soluble VEGF receptor (sVEGFR)-2, sVEGFR-3, interleukin (IL)-8 (n=105), and stromal cell-derived factor (SDF)-1α (n=28). Pre-treatment levels were compared between tumour types and correlated with response, progression-free (PFS), and overall survival (OS). Changes in circulating myelomonocytic and endothelial cells were also analysed., Results: Stromal cell-derived factor-1α and sVEGFR-2 levels were higher in pNET than in carcinoid (P=0.003 and 0.041, respectively). High (above-median) baseline SDF-1α was associated with worse PFS, OS, and response in pNET, and high sVEGFR-2 with longer OS (P⩽0.05). For carcinoid, high IL-8, sVEGFR-3, and SDF-1α were associated with shorter PFS and OS, and high IL-8 and SDF-1α with worse response (P⩽0.05). Among circulating cell types, monocytes showed the largest on-treatment decrease, particularly CD14+ monocytes co-expressing VEGFR-1 or CXCR4., Conclusions: Interleukin-8, sVEGFR-3, and SDF-1α were identified as predictors of sunitinib clinical outcome. Putative pro-tumorigenic CXCR4+ and VEGFR-1+ monocytes represent novel candidate markers and biologically relevant targets explaining the activity of sunitinib.

Introduction: For many tumors, the overexpression of the chemokine receptor CXCR4 is associated with increased malignancy and poor patient outcomes. However, comprehensive data for neuroendocrine neoplasms of the lung are still lacking., Methods: CXCR4 expression was evaluated in a panel of bronchopulmonary neuroendocrine neoplasms (BP-NEN) comprising typical carcinoids (n = 26), atypical carcinoids (n = 30), and small cell lung cancers (SCLC, n = 34). Samples were analyzed by immunohistochemistry using the novel monoclonal rabbit anti-human CXCR4 antibody UMB-2 and by qRT-PCR. The expression was correlated with clinical data and overall patient survival., Results: CXCR4 was predominantly localized at the plasma membrane of the tumor cells. CXCR4 was expressed with a high intensity in almost all of the 30 SCLC samples. In contrast, it was detected infrequently and with low intensity in the typical carcinoid and atypical carcinoid samples. There was a significant correlation between the immunohistochemistry and qRT-PCR data. Additionally, there was a significant negative relationship between CXCR4 expression and overall survival., Conclusions: With increasing malignancy, BP-NEN clearly differ in the extent of CXCR4 expression. As in other tumor entities, CXCR4 overexpression significantly correlates with negative patient outcome. Due to its particular high expression rate in SCLC, CXCR4 may serve as a promising new target for diagnostic and pharmacological intervention as well as for peptide receptor-based radionuclide therapy.

Objective: Data on clinical presentation and associated features of patients with type 1 gastric carcinoids (T1-GCs) are scanty. This study aimed to provide detailed data on a series of patients with T1-GCs., Material and Methods: Clinical, laboratory, endoscopic, and histological data were assessed from 31 T1-GCs patients (cross-sectional design), consecutively diagnosed in a tertiary center according to a standardized diagnostic protocol. T1-GCs were diagnosed at baseline or follow-up gastroscopy for atrophic gastritis in 74.2% and 25.8% of patients, respectively., Results: Seventy-one percent of T1-GC patients were female. Age ranged from 23 to 78 (median 58 years). T1-GCs were more frequently diagnosed between 40-49 years (35.5%) and 60-69 years (32.3%) (p = 0.0383). Thyroid disease was present in 54.8% (in 29% autoimmune). All 31 patients had either cobalamin or iron deficiency with or without anemia. Manifest pernicious anemia was present in 67.7% of patients and cobalamin deficiency without anemia in 9.7% patients. Iron deficiency anemia was present in 29% and iron deficiency without anemia in 12.9% of patients. In 48.4% of patients, T1-GCs appeared as polyps, which were single in all cases and had a median size of 4 mm (range 2-15 mm). In patients with polypoid T1-GCs, thyroid disease of autoimmune and nonautoimmune origin (p = 0.0181) was more frequently associated., Conclusion: This study shows that T1-GCs may be diagnosed at any age. Autoimmune features are frequently present as well as cobalamin and iron deficiency. The copresence of autoimmune diseases and micronutrient deficiencies should be accurately investigated, in particular in patients with polypoid T1-GCs.

Context: Gastric type I carcinoid is a rare neoplasm, deriving from enterochromaffin-like cells (ECL), mainly affecting women with autoimmune gastritis. The approach to treatment, either endoscopic, medical or surgical, is not well defined, particularly in multifocal tumours or carcinoids with rapid growth/frequent recurrence., Objective: To determine whether an anti-G17 vaccination might interfere on the natural history of gastric type I carcinoid., Setting: Padua teaching Hospital, outpatient clinic., Design and Patients: Three patients with type I gastric carcinoid in autoimmune gastritis were administered, after informed consent and ethic committee approval, with a vaccine against gastrin 17 (G17), a synthetic peptide that stimulates specific and high-affinity anti-G17 antibodies, and followed up endoscopically and clinically for a mean of 36 months., Main Outcome Measures: Gastric histology and specifically carcinoid growth/recurrence and trend in time in gastrin, G17, pepsinogens, chromogranin A and clinical parameters., Results: Following vaccination, carcinoid regression was observed in 2/3 patients and, in one of the patients, even the disappearance of ECL hyperplasia, with a reduced ECL cells stimulation, confirmed by a significant reduction in chromogranin A levels. Regression was observed in the two patients that showed a more clear local response to the vaccine. Increased autoantibody titre was observed, but no appearance of new autoimmune diseases., Conclusions: Anti-G17 vaccination induced regression of type I gastric carcinoid and could be considered for the treatment of this tumour, when endoscopic removal is not indicated.

Appendiceal tumors exhibiting both neuroendocrine and glandular differentiation are uncommon and have caused difficulty in pathologic classification, prediction of prognosis, and clinical management. Previously, such lesions have been variously designated as adenocarcinoid, goblet cell carcinoid (GCC), and mixed adenocarcinoma carcinoid. In this study, we undertook a retrospective investigation of 63 such cases and classified them as typical GCC (group A) and adenocarcinoma ex GCC on the basis of the histologic features of the tumor at the primary site. The adenocarcinoma ex GCC group was further divided into signet ring cell type (group B) and poorly differentiated adenocarcinoma type (group C). The clinical characteristics and prognosis were compared within these groups and with conventional de novo appendiceal adenocarcinomas. Both groups A and B tumors shared a similar immunoprofile, which included generally focal immunoreactivity for neuroendocrine markers, and a normal intestinal type mucin glycoprotein profile (negative MUC1 expression and preserved MUC2 immunoreactivity). The proliferative index was relatively low in these tumors and slightly increased from groups A to B tumors (11% to 16%). Both beta-catenin and E-cadherin exhibited a normal membranous staining pattern in groups A and B tumors. The poorly differentiated adenocarcinomas ex GCC (group C) demonstrated abnormal p53 and beta-catenin immunoreactivity. The mean follow-up time was 49+/-5 (SE) months. The overall disease-specific survival for all subtypes was 77%, with 46% of patients without evidence of disease and 31% alive with disease. The mean survival was 43+/-7 months. All the patients with clinical stage of I or IIA disease had a favorable outcome after appropriate surgery with or without chemotherapy. Although most patients (63%) with GCC presented at an advanced clinical stage, their clinical outcome could be differentiated by subclassification of tumors. The stage IV-matched 5-year survival was 100%, 38%, and 0% for groups A, B, and C, respectively. In conclusion, GCC is a distinctive appendiceal neoplasm that exhibits unique pathologic features and clinical behavior. They display a spectrum of histologic features and possess the potential to transform to an adenocarcinoma phenotype of either signet ring cell or poorly differentiated adenocarcinoma types. Careful evaluation of the morphologic features of GCCs and appropriate pathologic classification are crucial for clinical management and prediction of outcome. Surgical management with right hemicolectomy is recommended after appendectomy for most cases, particularly those with an adenocarcinoma component (groups B and C).

Gastrointestinal carcinoid is a rare tumor. The association of this tumor with chylous ascites is uncommon. A review of the English-language literature carried out in 2002 identified only 15 cases. We report a case of chylous ascites, gastrointestinal carcinoid tumor and elevated blood levels of CA-125 in a patient who did not respond to chemotherapy.

Goals: Our aim was to elucidate the incidence and distribution pattern of ghrelin-immunoreactive (IR) cells in various types of human gastric endocrine tumors, and their surrounding mucosa, and relate the findings to total ghrelin concentrations in plasma., Background: It has been demonstrated previously, that ghrelin-IR cells are present not only in normal human gastric oxyntic mucosa, but also in all types of enterochromaffinlike (ECL) cell carcinoids (ECL-CCs), and in mucosal regions affected by ECL cell hyperplasia., Study: Forty-eight gastric endocrine tumors were included in the study: 32 type I ECL-CCs, 3 type II, 9 type III, 1 non-ECL-CC, and 3 poorly differentiated endocrine carcinomas. The tumors were analyzed immunohistochemically with antibodies raised versus chromogranin A, synaptophysin, serotonin, somatostatin, vesicular monoamine transporter 2 and ghrelin. Total ghrelin in plasma was measured in 20 patients, using a commercial radioimmunoassay kit., Results: Ghrelin-IR cells were found in all types I and II ECL-CCs but in only a few cases of the other tumors. Ghrelin-IR cells were also found among the hyperplastic endocrine cells in the mucosa surrounding types I and II, where they showed diffuse, linear, nodular and adenomatoid hyperplasia patterns. In type III ECL-CCs and poorly differentiated endocrine carcinomas, only diffuse and linear ghrelin-IR cell hyperplasia was present in the oxyntic mucosa in about half of the cases, whereas the mucosa of the non-ECL-CC did not show this feature., Conclusions: Despite the frequent occurrence of ghrelin-IR cells in both the neoplastic parenchyma and the oxyntic mucosa, plasma total ghrelin concentrations remained within the reference range and can therefore not be used as a clinical marker to identify ghrelin expressing ECL-CCs or ghrelin cell hyperplasia.

The authors describe a case of goblet-cell carcinoid of the appendix subject to additional immunohistological study. Goblet-cell carcinoid is a rare colonic tumor comprises the morphological signs of adenocarcinoma and carcinoid.

Purpose: The aim of the study was to identify immunogenic HLA-A*0201-binding epitopes derived from a number of classical midgut carcinoid-associated proteins. CD8(+) T cells recognizing tumor-associated antigen (TAA) epitopes are of great interest for the establishment of immunotherapy as a novel treatment for this type of malignancy., Experimental Design: Midgut carcinoid tumor specimens were microdissected and expression levels of potential TAAs were investigated by quantitative real time PCR. HLA-A*0201-binding motifs were selected using HLA peptide binding prediction algorithms and stabilization of HLA-A*0201 was verified using TAP-deficient T2 cells. Peripheral blood of midgut carcinoid patients was analyzed for peptide epitope recognition and the feasibility of generating peptide-reactive CD8(+) T cells in healthy blood donors was examined by an in vitro stimulation protocol using mature DCs. Activation of patient and healthy donor CD8(+) T cells was analyzed by intracellular flow cytometry staining of interferon gamma., Results: Chromogranin A (CGA), tryptophan hydroxylase 1 (TPH-1), vesicular monoamine transporter 1 (VMAT-1), caudal type homeobox transcription factor 2 (CDX-2), and islet autoantigen 2 (IA-2) are properly expressed by midgut carcinoid tumor cells, with CGA mRNA expressed to greatest level. Midgut carcinoid patients have increased frequencies of peripheral blood CD8(+) T cells recognizing a pool of HLA-A*0201 peptides derived from these proteins compared to healthy age-matched individuals. Activated peptide-specific CD8(+) T cells could also be generated in healthy blood donors by in vitro stimulation., Conclusion: We have identified a number of immunogenic midgut carcinoid-associated peptide epitopes recognized by CD8(+) T cells. We show that midgut carcinoid patients display immune recognition of their tumors. Memory CD8(+) T cells in patient blood are of great interest when pursuing an immunotherapeutic treatment strategy.

Amino acid transport systems play an important role in cellular proliferation. L-type amino acid transporter 1 (LAT1) has been associated with tumor growth, and is highly expressed in the established tumor cell lines and primary human neoplasms. In this study, we investigated the expression of LAT1 to evaluate the malignant potential and prognostic significance in neuroendocrine (NE) tumors of the lung. Twenty-one surgically resected, large cell neuroendocrine carcinomas (LCNEC), 13 small cell lung cancers (SCLC), five atypical carcinoids (AC), and 10 typical carcinoids (TC) were enrolled in the study. LAT1 expression and Ki-67 labeling index of the NE tumors were analyzed by immunohistochemical staining. LAT1 was overexpressed in 52.4% of the LCNEC, in 46.2% of the SCLC, and in 25% of the AC. LAT1 expression in LCNEC was significantly associated with lymph node metastasis and poor outcome. Moreover, a significant correlation was found between LAT1 expression and Ki-67 in both LCNEC and SCLC. Expression of LAT1 tended to increase from low-grade to high-grade NE tumors. The present results suggest that LAT1 may play a significant role in cellular proliferation, lymph node metastasis, and poor outcome in patients with NE tumors of the lung.

We report immunohistochemical (IHC) and molecular findings in a rare case of a carcinoid tumor of the extrahepatic bile ducts in a 33-year-old woman, who presented with a 3.9x2.8x2.6 cm mass within the right and common hepatic ducts. She underwent surgery and a carcinoid tumor was identified. This lesion is of interest because in addition to the morphological and cytological features of a typical carcinoid, it demonstrated a distinct pleomorphic area immunoreactive for gastrin. By molecular analysis, loss of heterozygosity (LOH) with opposite allelic patterns between the gastrin-positive and gastrin-negative areas of the tumor was identified. The molecular studies for LOH along with the morphology and IHC profiling suggest that this second population of gastrin-positive carcinoid cells may represent a new clone within the carcinoid tumor with differentiation toward gastrin production or may represent the next step in the carcinogenic process with a gradual emergence of a more aggressive clone.

In order to understand the stromal reaction associated with colorectal neoplasms, we examined specimens from 26 patients including normal colorectal tissues (n=15), carcinoid tumors (n=12), well differentiated adenocarcinomas (n=10), and poorly differentiated adenocarcinomas (n=4), using an immunohistochemical method. Myofibroblasts and CD34-positive stromal cells were distributed in the mucosa and in the area between the submucosal and subserosal layers, respectively. However, the distribution of these cells markedly changed with the invasion of neoplasms. Namely, myofibroblasts were abundant in the invasive stroma of all colorectal neoplasms. CD34-positive stromal cells were completely absent from the invasive stroma of colorectal cancers. On the other hand, CD34-positive stromal cells were absent from four out of five carcinoid tumor cases with lesions measuring less than 2 mm in size, but were present in all seven cases of carcinoid tumors measuring more than 2 mm. Double-immunostaining identified stromal cells expressing both ASMA and CD34 in several carcinoid tumor cases. Finally, no CD34-positive stromal cells were observed in the invasive stroma of colorectal cancers. However, the distribution of these cells in carcinoid tumors may depend on the lesion size. Namely, CD34-positive stromal cells existed between neoplastic nests in large-sized carcinoid tumors. Myofibroblasts in the stroma of colorectal neoplasms may originate from CD34-positive stromal cells.

The long-term evolution of Hu antibody (Hu-Ab) titers in patients with paraneoplastic neurologic syndromes (PNSs) is not known. Described is the evolution of Hu-Ab titers in 35 patients with PNS with a median follow-up of 32 months (range 6 to 108 months). No correlation was observed between Hu-Ab titers and neurologic outcome, tumor evolution, or type of treatment. Serial Hu-Ab determinations are not useful for monitoring the clinical outcome of patients with PNS.

Telomerase activity was examined by the telomeric repeat amplification protocol (TRAP) assay in 38 neuroendocrine (NE) lung tumours. A significantly (p = 0.001) different frequency of telomerase positivity was observed among different histological tumour types. Specifically, a positive TRAP signal was observed in 14 of 15 (93%) small cell lung cancers (SCLCs), 7 of 8 (87%) large-cell NE carcinomas (LCNECs), and only 1 of 15 (7%) typical carcinoid tumours. When telomerase activity was correlated with the gene product-based immunophenotypic profile of individual tumours, it was found that the absence of telomerase activity was associated with a lack of bcl-2, p53, and c-kit expression, and characterized by a low proliferation index consistent with the absence of cdk-4 expression and the presence of the cdk inhibitor Rb. Such a phenotype was appreciable in most of the carcinoid tumours. Conversely, telomerase-positive tumours generally showed an immunophenotype consistent with gene product alterations (including high expression of bcl-2, p53, and c-kit, and loss of Rb) and were characterized by a high proliferation index. These telomerase data support the previously reported evidence for two genetically unrelated groups of NE lung tumours (SCLC, and to some extent LCNEC, versus carcinoid tumours) that have distinct phenotypic profiles., (Copyright 2003 John Wiley & Sons, Ltd.)

Background: Gastric carcinoid is a rare tumour that is associated with chronic atrophic gastritis in the majority of cases. It usually occurs in the 6th or 7th decade of life and is rarely diagnosed in patients under 30 years of age., Methods: We describe a case of multiple gastric carcinoids in a 23-year-old woman with systemic lupus erythematosus and atrophic autoimmune gastritis--an association that has not been reported previously., Results: The combination of atrophic autoimmune gastritis and gastric carcinoid with other autoimmune disorders has rarely been reported in the English medical literature., Conclusion: The fact that it mostly concerns (relatively) young patients may suggest a potential causative relation between those autoimmune disorders and the early development of atrophic gastritis with hypergastrinaemia, which subsequently leads to the occurrence of gastric carcinoid tumours at a young age.

Background: Metastatic carcinoid tumours are difficult to manage. In spite of a multidisciplinary approach, including orthotopic liver transplantation, the recurrence rate is high with a poor prognosis. Histopathology generally fails to provide prognostic information, hence it is essential to try to identify markers of prognosis in these tumours before considering orthotopic liver transplantation. The MIB-1 antibody, which detects cell proliferative activity, has been shown to be a useful prognostic marker for a variety of neoplasms., Aims: To assess the value of MIB-1 immunostaining as a prognostic marker of the duration to recurrence and the survival of patients undergoing orthotopic liver transplantation for metastatic carcinoid/neuroendocrine tumours of the liver., Methods: Fourteen patients were included in the study. Formalin-fixed, paraffin-embedded tissue sections of the tumours were stained with routine haematoxylin and eosin and chromogranin. The cell proliferative activity was assessed by MIB-1 antibody labelling using the immunoperoxidase method. Results were correlated with the time of tumour recurrence and the length of patients' survival after transplantation., Results: No correlation was found between MIB-1 labelling index and age, gender, clinical and histological type of tumour (i.e. carcinoid, APUDOMA, secreting or non-secreting). The patients with higher MIB-1 indices ( 5%) showed a trend toward earlier recurrence and poorer survival than those with low MIB-1 indices ( 5%). The predictive value of a MIB-1 index of 2 indicating patient survival of 24 months was 83% (five out of six patients)., Conclusions: The correlation between MIB-1 index and patients' survival suggests that a high proliferative rate, as assessed by MIB-1 immunostaining, may detect those tumours with more aggressive biological behaviour. Prospective studies on a larger number of patients will be needed to determine if, in any individual tumour, this method will provide an additional parameter for a rational approach to therapy.

Natural killer (NK) and CD56(+) T cells are thought to play a central role in antitumour immunity. Their cytolytic activities are controlled by a variety of receptors including CD94 and killer immunoglobulin-like receptors (KIR), which bind to major histocompatibility complex (MHC) class I molecules on target cells and mediate cell activation or inhibition. We have examined the numbers, phenotypes and antitumour cytotoxic functions of hepatic NK and CD56(+) T cells isolated from 22 patients with hepatic malignancy and 19 healthy donors. Flow cytometry revealed that NK cell numbers were increased among hepatic mononuclear cells in malignancy compared to histologically normal livers (mean: 38% vs 27%; P=0.03), but CD56(+) T cell numbers were not (28% vs 27%). NK cells and CD56(+) T cells from tumour-bearing livers exhibited lymphokine-activated killing of K562 targets and T cell receptor-mediated lysis of P815 cells. The expression of CD94 and the KIR isotypes CD158a, CD158b and KIR3DL1 by CD56(+) T cells and NK cells was significantly and consistently reduced in tumour-bearing livers compared to healthy livers ( P<0.05 in all cases). Simultaneous ligation of CD158a, CD158b and KIR3DL1 caused an overall partial inhibition of CD56(+) T cell cytotoxic activity, suggesting that the observed reductions in KIR(+) cell numbers in malignancy are likely to lead to enhanced cytotoxicity. Our results suggest that, while hepatic CD56(+) T cells are not expanded in malignancy, downregulation of KIR and CD94 expression may be a mechanism by which the hepatic immune system can be activated to facilitate tumour rejection.

The study aimed at immunocytochemical evaluation of the cellular expression of two cytokines, IL-2 and IL-12 in lung carcinoids (n = 10), following the earlier demonstration of two markers of endocrine tumours (chromogranin A and NSE--neuron-specific enolase). In the immunocytochemical studies the classical avidin-biotinylated peroxidase (ABC) technique was used. Results of the tests were semiquantitatively appraised employing the IRS scale. In 9/10 cases intense reaction (score: 6-12 points) was noted for both lung neuroendocrine markers. In all cases of carcinoma co-expression of IL-2 and IL-12 was demonstrated in cells of the tumours. The cytokines showed a cytoplasmic localisation of mean (score: 3-4 points) or high (score: 6-12 points) intensity of reaction. Our studies point to a possible role of the two cytokines in the proliferation of lung neuroendocrine carcinomas but more detailed analysis is required on a broader material.

The induction of apoptosis in dendritic cells (DC) is a key mechanism by which tumors escape immune recognition and elimination. In fact, a number of studies have showed the correlation between the number of DC within the tumor and the clinical prognosis, suggesting that increased infiltration of tumor tissue by DC was associated with better patient survival and low incidence of metastatic disease. We compared the number of DC and their distribution pattern in human small-cell lung carcinoma and bronchial carcinoid tumor (CT) tissues. Immunohistochemical analysis revealed the presence of cells expressing DC markers CD1a and CD83 in small-cell lung carcinoma tissues and the complete absence of these cells in CT samples. Next, we examined whether human lung tumor cells produce soluble factors that inhibit differentiation of hematopoietic precursors into mature DC. The addition of small-cell lung carcinoma-conditioned medium to CD34+ precursor cell cultures significantly inhibited colony-forming units of DC formation when compared with nontreated control DC cultures. Furthermore, DC generation and differentiation was completely abrogated in CD34+ cell cultures treated with CT-conditioned medium, suggesting that CT-derived factors blocked CD34+ cell differentiation into DC or induced their apoptosis. Finally, flow cytometry analysis of cultured DC confirmed these results. Thus, analysis of our data suggests that human lung tumors produce factors that inhibit DC generation or maturation and may also induce apoptotic death of DC precursors in vitro.

Background: About 50% of patients with thymoma have paraneoplastic myasthenia gravis (MG). Myositis and myocarditis or neuromyotonia (NMT) will also develop in some. Patients with thymoma-associated MG produce autoantibodies to a variety of neuromuscular antigens, particularly acetylcholine receptor (AChR), titin, skeletal muscle calcium release channel (ryanodine receptor [RyR]), and voltage-gated potassium channels (VGKC)., Objective: To examine whether neuromuscular autoantibodies in patients with thymoma correlate with specific clinical syndromes., Methods: Serum and plasma samples from 19 patients with thymoma-associated MG, of whom 5 had myositis and 6 had NMT, underwent testing for antibodies to AChR, titin, RyR, and VGKC., Results: Antibodies to AChR and titin were found in 19 and 17 patients, respectively. Antibodies to RyR correlated with the presence of myositis (P = .03); they were found in all 5 patients with myositis and in only 1 patient with NMT, but also in 4 of 8 patients with neither disease. Antibodies to VGKC were found in 4 patients with NMT, 1 of 3 patients undergoing testing for myositis, and 2 of 7 patients undergoing testing with neither comorbidity. Presence of RyR antibodies correlated with high levels of titin antibodies., Conclusions: The results appear to distinguish partially between 3 groups of patients with thymoma-associated MG: the first with RyR antibodies and myositis or myocarditis, the second with NMT without RyR antibodies, and the third without RyR antibodies, myositis, or NMT. Differences in the thymoma may underlie these pathologic associations.

A potential upregulation of receptor type protein tyrosine phosphatase IA-2 (ICA512) expression was detected by differential display and investigated in midgut carcinoid tumours. Normal intestine tissue and tumour tissue from 13 midgut carcinoid patients were studied by in situ hybridisation using an IA-2 ribonucleotide probe and confocal microscopy using specific IA-2 antibodies. Previously, it had been shown that IA-2 is located in the secretory granules of virtually all neuroendocrine cells. However, we found that IA-2 was not detectable in resting normal enterochromaffin (EC) cells of the small intestine, while high expression of IA-2 mRNA and protein was confirmed in both primary and metastatic carcinoid tissue. This difference in expression was not observed with chromogranin A or serotonin, two secretory granule hormones known to be expressed in EC cells, indicating that IA-2 was seemingly not necessary for the basal production and packaging of these hormones. When comparing patients receiving biotherapy before operation with untreated patients, we found expression of IA-2 to be lower in tumours from patients that had been treated with a combination of alpha-interferon and the somatostatin analogue, octreotide. There was no correlation between IA-2 expression and proliferation rates as measured by immunohistochemistry with antibodies against the Ki 67 antigen. Furthermore, we show that IA-2 is co-localised with serotonin in carcinoid tumours as well as in the pancreatic tumour cell line, BON1, which is interesting as serotonin secretion rate is presumably higher in tumour cells than in resting EC cells. Taken together, these findings may indicate a role for IA-2 in the later stages of the regulated secretory process.

Carcinoid tumours of the gastrointestinal tract are often associated with other tumour types at various sites. However, only rarely has a lymphoma constituted the second tumour. In the present paper, we report the case of a 62-year-old woman who was operated on for a perforated T-cell lymphoma of the ileum and in whom an appendicular carcinoid tumour was incidentally discovered at surgery. It was possible to completely remove both tumours and postoperatively the patient underwent CHOP treatment. Ten months after surgery the patient is well, with no tumour manifestations. We also discuss problems concerning classification of the lymphoma on account of loss of the T-cell antigen CD45RO (UCHL-1).

We report a case of a 62-year-old woman with goblet cell carcinoid of the appendix. She was admitted to our hospital in September 1994 after the discovery of liver tumors. After admission, a tumor in the right kidney and multiple tumors in the liver were found. She was diagnosed with renal cell cancer and metastasis to the liver and underwent excision of the kidney and enucleation of the largest liver tumor. Histological examination revealed that the liver tumor was a metastatic carcinoid tumor. As carcinoid tumors have frequently been found in the appendix, endoscopic examination was performed and a lesion was found in the appendix by colonoscopy. As predicted, the biopsy specimen was a carcinoid tumor, and she underwent an appendectomy. Histologically, the tumor was a goblet cell carcinoid. Goblet cell carcinoid is a rather rare neoplasm that has the histologic features of both carcinoids and adenocarcinoma. Forty-two cases of goblet cell carcinoid of the appendix have been reported thus far in Japan. However, few were diagnosed via endoscopic examination before surgical operation. We also carried out an immunohistochemical study with anti p53 antibody on the goblet cell carcinoid tumor of the appendix. Most tumor cells were strongly positive, while in three benign carcinoid tumors investigated simultaneously they were negative. These findings suggest that goblet cell carcinoid has an aggressive phenotype compared with benign carcinoid tumors.

Alpha interferons have become effective palliative treatments for patients with neuroendocrine tumours such as carcinoids and endocrine pancreatic tumours. However, several reports indicate an increased incidence of both autoantibodies and autoimmune diseases in patients treated with interferon-alpha (IFN-alpha). We studied the development of antibodies against double-stranded DNA (dsDNA) and clinical signs of autoimmune disease in 214 patients with malignant carcinoids or endocrine pancreatic tumours consecutively admitted for treatment with IFN-alpha. Seventeen patients (8%) developed antibodies against dsDNA, predominantly females (12 females and 5 males). One patient had clinical and laboratory signs of polymyositis. Among the other 16 patients, three developed hypothyroidism and in six patients the anti-dsDNA autoantibodies normalized despite continuing therapy. Although a significant number of patients developed autoantibodies against dsDNA, overt autoimmune disease related to these antibodies is a rare event and many patients spontaneously normalize these titres despite continuing IFN-alpha treatment.

Immune responses elicited by allergic reactions and parasitic worm infections are characterised by the induction of T helper 2 (Th2) cells. These cells secrete cytokines such as interleukin-4 (IL-4), IL-5 and IL-13, which induce the production of immunoglobulin E (IgE) and eosinophils [1,2]. Previous studies using gastrointestinal nematodes to elucidate the role of Th2-cell-mediated immune responses have demonstrated a causal relationship between T cells and worm expulsion (reviewed in [3]). Although it has been proposed that IL-4 played a central role in these responses, recent studies demonstrated that IL-4-/- mice expel the parasitic gastrointestinal nematode Nippostrongylus brasiliensis normally [4], suggesting that another T-cell mediator is required for efficient worm clearance. Using IL-13-/- mice, we have demonstrated that, unlike wild-type and IL-4-/- mice, the IL-13-/- animals failed to clear N. brasiliensis infections efficiently, despite developing a robust Th2-like cytokine response to infection. Furthermore, treatment of the IL-13-/- mice with exogenous IL-13 resulted in a reduction in the numbers of worms recovered. The IL-13-/- animals also failed to generate the goblet cell hyperplasia that normally occurs coincident with worm expulsion. This observation may link IL-13 with the production of intestinal mucus which is believed to facilitate worm expulsion. These data support a unique role for IL-13 in Th2-cell-mediated immune responses and demonstrate that IL-13 and IL-4 are not redundant.

Primary biliary cirrhosis (PBC) is frequently associated with other autoimmune disorders. Although antibodies against gastric parietal cells are found in nearly all PBC patients, autoimmune gastritis is only very rarely associated. We describe a woman with PBC in whom chronic autoimmune gastritis complicated by a large pedunculated gastric carcinoid tumor was found. Additionally, the patient had autoimmune thyroiditis. This was interpreted as the rare association of PBC with Schmidt's syndrome type III. The carcinoid tumor was removed endoscopically. We conclude from the case that an endoscopic screening for autoimmune gastritis should at least be performed in patients with PBC and autoimmune thyroiditis, keeping in mind the possible occurrence of a polyendocrinopathy and the potentially serious complication of a gastric carcinoid tumor.

Neuroendocrine-specific protein (NSP)-reticulons are endoplasmic reticulum-associated protein complexes, which have been identified as markers for neuroendocrine differentiation. In this study, the expression of two members of the family of NSP-reticulons, NSP-A and NSP-C, have been investigated in different types of lung cancer and compared with the expression patterns of five conventional neuroendocrine markers, the neural cell adhesion molecule (NCAM), synaptophysin, chromogranin A, Leu-7, and neurofilament proteins. NSP-A and NSP-C antibodies were reactive with most carcinoid tumour and small cell lung carcinoma (SCLC) cases, while atypical carcinoid tumours showed a variable expression. In the total group of neuroendocrine tumours, a high concordance of expression was found between NSP-A and NSP-C, while their expression correlated well with NCAM and synaptophysin positivity. Chromogranin A, Leu-7, and neurofilament proteins were shown to be expressed to a limited extent in these neuroendocrine tumours. In a selected group of non-SCLCs known to exhibit neuroendocrine features, NSP-A expression was detected at much higher frequency than NSP-C. In virtually all NSP-A positive cases, this expression was associated with one or more of the other neuroendocrine markers. NSP-A expression showed a stronger correlation with conventional neuroendocrine markers than NCAM. In detecting neuroendocrine differentiation in non-SCLC, NSP-A is more sensitive than synaptophysin, chromogranin A, Leu-7, and neurofilament proteins. It is concluded that NSP-reticulons are valuable markers in the diagnosis of neuroendocrine differentiation in non-SCLC and should be used in conjunction with NCAM.

It is well known that natural and recombinant proteins can cause antibody formation in the host. We have studied the incidence of binding and neutralizing antibodies in carcinoid patients (n = 327). All together 204 patients received interferon-alpha 2b (Intron-A), median does 15 MU range 9-35 MU/week subcutaneously and 51% of the patients developed binding antibodies by immunoassay and 17% showed positive neutralization assay but high titer antibodies (> 800 NU/ml) were only found in 4% of the patients. The median time until the development of binding antibodies was 26 months and neutralizing antibodies 25 months. Twenty-nine patients received interferon-alpha 2a (Roferon), median does 18 MU/week subcutaneously and 45% developed binding antibodies, 38% had positive neutralization assay and 28% presented high titer antibodies. Binding and neutralizing antibodies occurred at the same time after median six months of treatment. Patients treated with Wellferon (n = 45) and leukocyte interferon (n = 48), median dose of 15 MU/week subcutaneously did not develop any neutralizing antibodies. The majority of the interferon-alpha 2 antibodies were of the IgG isotype. The clinical relevance of the development of high titer neutralizing antibodies was evaluated in the patients. All together 17 patients developed high titer neutralizing antibodies and of these 12 patients showed loss of antitumor response measured as increased level of tumor markers and of tumor progression. In nine of these patients a switch to human leukocyte interferon reinstituted an antitumor response. Neutralizing antibodies against recombinant interferon-alpha 2a and 2b might occur in patients with carcinoid tumors. The incidence of high titer neutralizing antibodies is significantly higher in patients treated with interferon-alpha 2a compared to interferon-alpha 2b. A significant number of patients lost the antitumor effect during development of neutralizing antibodies at high titers, but human leukocyte interferon can be used as rescue treatment.

Stellate-shaped S-100 protein positive sustentacular cells (SCs) appear to correlate inversely with the degree of tumor malignancy in some neuroendocrine tumors. Therefore, the SCs have been investigated in carcinoid pulmonary tumorlets and subsequently examined quantitatively in order to provide a basis for estimation of this phenomenon in tumorlet related lesions, especially carcinoids and neuroendocrine carcinomas. Pulmonary tissue from twenty-four patients with carcinoid tumorlets was studied immunohistochemically for S-100 protein positive SCs together with glial fibrillary acidic protein, actin, desmin, vimentin and cytokeratins. Tumorlet SCs were calculated per 10,000 tumorlet elements. The presence of SCs was proven in 18 subjects (75%) of all examined cases with quantitative frequency between 13 and 196 SCs per 10,000 tumorlet elements. The histogram showed three separate clusters of cases. Cluster 2 and cluster 3 with strikingly high frequency of SCs, i.e. from 66 up to 196 SCs per 10,000 tumorlet cells, may represent the biphasic differentiation potential of tumorlet elements. The mentioned lesions could be regarded as the possible precursors of pulmonary paragangliomas or paraganglioid carcinoids.

The jejunoileum and the right colon, both of which are located in the midgut, have some histologic similarities such as the presence of Paneth cells and intraepithelial endocrine cells (IEECs). Since gastrointestinal (GI) carcinoids arise from the same stem cells as GI endocrine cells, the question was whether or not there might also be similarities in the histogenesis of jejunoileal carcinoids (JICs) and right colonic carcinoids (RCCs). Ten single JICs and 3 RCCs together with their respective controls were stained using various neurohormonal immunoreagents. Our results showed that neither the JICs nor the RCCs appeared to arise from a background of diffuse IEEC hyperplasia. Furthermore, in the jejunoileum, serotonergic progenitor cells appear to have a proclivity for neoplastic transformation, as do cells of the pancreatic polypeptide and glucagon lineage in the right colon.

Objectives: Islet cell antibodies (ICA) in sera of patients with autoimmune diabetes mellitus generally stain not only the insulin-producing beta cells but also the non-beta cells of the islets of Langerhans. The antibodies have been reported to react also with the chromaffin cells of carcinoid tissue. In the present study, we examined in detail the reactivity of 10 ICA-positive sera of patients with new onset insulin-dependent diabetes mellitus (IDDM) and two sera of patients with stiff-man syndrome., Design: The sera were analysed by immunofluorescence and by immunoperoxidase staining of human islets as well as by immunoprecipitations using 35S-methionine labelled rat islet lysates. In addition, immunofluorescence analyses of carcinoid tissues were carried out., Results: Eight of the 10 IDDM-positive sera reacted with all islet endocrine cells, whereas two sera showed staining restricted to the beta cells, as did the two sera of the patients with stiff-man syndrome. All beta cell 'selective' sera, but only 6 of 8 'whole' islet positive sera, immunoprecipitated the 64.kDa glutamic acid decarboxylase (GAD) antigen. The staining of carcinoid tissue was variable and did not correlate with the 'whole' or 'selective' staining pattern of islets., Conclusion: The data underline a heterogeneity of ICA and indicate the presence of a separate, non-GAD antigen in islet cells. It is possible that in future studies, a resolution of ICA titres with respect to different types of islet cellular reactivity might provide insights into the pathogenesis of IDDM and improve the prognostic implications of antibody determinations.

Background: Gastrointestinal neoplastic epithelium of glandular origin commonly produces N-linked and O-linked glycoproteins such as carcinoembryonic antigen (CEA) and tumor-associated polymorphic epithelial mucin (PEM). Antibodies to these glycoproteins increasingly are being used in immunodiagnosis and/or immunotherapy. Although GI carcinoid tumors have a neuroendocrine immunophenotype and generally have an indolent clinical course compared with their adenocarcinomatous counterparts, they also arise from undifferentiated crypt epithelium. The purpose of this study was to determine whether GI carcinoids similarly expressed epitopes for CEA and PEM., Methods: Thirty-nine GI carcinoid tumors from various topographic sites were analyzed by immunohistochemistry using the murine monoclonal antibodies B72.3, ACT19, and T84. The former two antibodies recognize epitopes in PEM, whereas the latter is an anti-CEA antibody, which was confirmed using enzyme-linked immunosorbent assays., Results: The majority of carcinoid tumors (74%), particularly jejunoileal carcinoids, reacted for ACT19 antibody, whereas considerably fewer reacted for B72.3 (31%) and T84 (26%). The extent of staining was also greatest with ACT19. The GI mucosa adjacent to or overlying the carcinoid tumors also stained for the various antibodies., Conclusions: The extent and degree of positivity of carcinoid tumors for ACT19 raises the possibility that this antibody may be used in the future for the radioimmunodiagnosis and/or immunotherapy of these tumors, particularly in cases that are multicentric, unresectable, or with metastatic disease.

Carcinoid tumor metastatic to the liver from the breast is very unusual. We report a rare case in which the patient underwent curative resection for metastatic lesions to the liver. She had undergone a modified radical mastectomy more than 1 year previously for breast cancer. Recently, it was found that plasma levels of carcinoembryonic antigen (CEA) was elevated, and abdominal ultrasonography detected a liver tumor. The patient underwent a lateral segmentectomy of the liver, resulting in normalization of plasma CEA levels. The resected specimen was diagnosed as carcinoid tumor by histological, immunohistochemical, and ultrastructural microscopic studies. Re-examination of the breast tumor proved it to be the primary carcinoid.

Neuroendocrine tumors of the digestive system are slowly growing neoplasms which often present pronounced fibrosis around tumor cells and in the peritoneal cavity. In this study, 23 midgut carcinoids and 7 endocrine pancreatic tumors were examined for the presence of TGF-beta with affinity-purified polyclonal antibodies raised against synthetic peptides coding for a specific region of latency-associated peptide sequences of TGF-beta 1, -beta 2, -beta 3, a rabbit anti serum against TGF-beta binding protein (LTBP) and a rabbit polyclonal antibody against TGF-beta type II-receptor (TGF-beta RII). Tumor cells from most tissues expressed all three isoforms of TGF-beta but LTBP was only weakly expressed. In stromal cells abundant expression of TGF-beta 2 and LTBP was found, whereas TGF-beta 1 and TGF-beta 3 were expressed only weakly. TGF beta RII immunoreactivity was observed mostly in the stromal cells. Tissue sections from 4 of these neuroendocrine tumors were also investigated by in situ hybridization. Strong signals on tumor cells were detected with TGF-beta 2 and TGF-beta 3 cRNA probes and also weakly with TGF-beta 1 and LTBP cRNA probe. Strong positive signals were observed on stromal cells with TGF-beta 2 and LTBP probe whereas only weak signals were observed on the stromal cells with TGF-beta 3 probe. Strong signals were detected on stromal cells with TGF-beta RII probe whereas no signals were observed on tumor cells. Our data suggest that TGF-beta might play an important role in the interaction of tumor and stromal cells. Thus TGF-beta might stimulate matrix production and angiogenesis of stromal cells, whereas tumor cells themselves are unaffected by the growth inhibitory activity of TGF-beta.

Twenty-nine samples of ex vivo ovarian and lung carcinomas were investigated for the relationship between the presence of mutated protein 53 (mp53) and cytotoxic susceptibility. Unaltered expression of MHC class I alleles was required for the cytotoxic susceptibility of tumour cells to the autologous ex vivo blood lymphocytes, i.e. all 4 sensitive tumours belonged to the group of 11 tumours without defect in MHC class I expression. In contrast, the susceptibility did not correlate with the presence of mp53, i.e. cases with mp53 were randomly distributed between the sensitive and resistant tumours (2/4 and 10/17 respectively). There was no correlation either between the p53 mutation and down-regulation of MHC class I alleles. The results suggest that in these tumours the mutated p53 is not the source of immunogenic peptides and that the lack of recognition of the tumours with mp53 is not caused by a defect in the expression of MHC class I molecules.

A case of antibody formation in a patient with carcinoid syndrome is described. The patient was treated with octreotide in dosages up to 1.5 mg/day. Serum samples were analysed for the presence of octreotide antibodies before and after 20 months of octreotide treatment. In-vivo 111In-octreotide scintigraphy was performed before and during therapy, and after antibodies had developed. Before treatment, no serum antibodies against octreotide were detected. After 20 months of treatment, they were detectable up to a 1:115 serum dilution. The serum binding of 125I-Tyr3-octreotide was blocked by adding excess unlabelled Tyr3-octreotide, indicating the presence of specific octreotide antibodies. Before treatment, a normal distribution of radioactivity in the spleen and kidneys, irregular uptake in the liver due to metastases, and a hot spot in the lower abdomen were found during 111In-octreotide scintigraphy. After antibodies had developed, increased radioactivity over the heart and high background radioactivity in the abdomen with only faint visualization of the spleen, liver, and kidneys were found, indicating a prolonged presence of 111In-octreotide in the blood resulting from its being bound to antibodies. Increased radioactivity was also seen at the injection sites of the drug in the upper legs. In-vitro incubation of biopsy tissue from this site with 125I-Tyr3-octreotide revealed diffuse guanosine triphosphate (GTP) independent specific binding, indicating non-G-protein linked binding of labelled octreotide. This report describes the characteristic abnormalities during in-vivo 111In-octreotide scintigraphy in a patient with octreotide antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)

The first two cases reported in the literature of patients with immune-mediated type A gastritis with microcarcinoids (as part of a polyglandular syndrome type II in one) in combination with chronic glomerulonephritis are presented. Immune-mediated type A gastritis appears to be another immunologic disorder that can be associated with chronic glomerulonephritis.

The expression of fucosylceramide (PC47H antigen) in 97 lung cancers and 4 extrapulmonary squamous cell carcinomas was examined with the use of a novel monoclonal antibody, PC47H, recognizing fucosylceramide specifically. The observed variation in fucosylceramide content was dependent on the degree of glandular differentiation in adenocarcinoma of the lung. Fucosylceramide was abundantly expressed in well differentiated adenocarcinoma of the lung and poorly expressed in poorly differentiated adenocarcinoma. Some squamous cell carcinomas of the lung reacted with this monoclonal antibody weakly, but the reaction was noted only at the periphery of the epithelial sheets. Extrapulmonary squamous cell carcinoma and small-cell carcinomas did not react with monoclonal antibody PC47H. Interestingly, large cell carcinomas of uncertain cell origin were all positive for fucosylceramide, which accumulated in the cytoplasm. At the ultrastructural level, fucosylceramide was located in the plasma membrane and unit membrane of the rough endoplasmic reticulum. On the other hand, carcinoembryonic antigen as an adenocarcinoma-associated tumor marker was expressed significantly in squamous cell carcinomas as well as adenocarcinomas. Taken together, fucosylceramide seems to be expressed preferentially in adenocarcinomas, and is closely linked to glandular differentiation. Thus it may be a better tumor marker than carcinoembryonic antigen.

The authors report a case of primary renal carcinoid in a 57-year-old woman in whom the diagnosis, established by histological findings, was confirmed by argyrophilia and immunohistochemical studies using anti-neuron-specific enolase, chromogranin A, serotonin and somatostatin antibodies. The clinical and pathological features of this rare renal tumor are discussed.

The expression of a proliferating antigen by Ki-67 immunohistochemistry was evaluated in 32 gastrointestinal carcinoids and in 5 pancreatic islet cell tumors. In the tissue sections the number of labelled nuclei was calculated per tumor area. The tumors were classified as low proliferating (less than 0.3 labelled cells/mm2), medium proliferating (0.3-1 labelled cells/mm2), and high proliferating (greater than 1 labelled cell/mm2). In 26 tumors obtained from patients receiving antitumor therapy (alpha-interferon) the proliferative activity was decreased. In treated midgut carcinoids the proliferative activity in metastatic tissue was significantly reduced (p less than 0.05). Though not statistically significant, primary midgut carcinoids collected from untreated patients displayed a lower proliferative activity than liver metastases. A survival analysis revealed that patients with tumors displaying low proliferative activity had a better survival than those with high proliferative activity (p less than 0.05). Single cell cytofluorometric DNA analyses showed regular diploid stem cell lines in the majority of tumors from untreated patients (9/11 cases). No correlation was found between the calculated proliferative activity and the DNA profile. The obtained results indicate that the expression of a proliferation antigen by Ki-67 immunohistochemistry can be used to evaluate the biological behavior of neuroendocrine tumors of the digestive system and predict survival.

One hundred and eighty-seven operable lung tumours were immunostained with the monoclonal antibody Ki-67 and divided into groups of high, moderate or low proliferation. Patients have been followed clinically for up to 7 years to ascertain whether this immunocytochemical measurement reflected tumour behaviour in terms of survival. The majority of the tumours were squamous cell carcinomas (104 cases) and adenocarcinomas (60 cases). These were divided into three groups of low, intermediate and high growth fraction, in which survival was better for tumours of lower proliferative rate up to approximately 2 years after operation. By 5 years these differences had largely disappeared and all tumours of a particular type showed a similar survival curve. Small cell carcinomas (13 cases) had high Ki-67 labelling indices, with more than 60% of patients deal in the first year, whereas carcinoid tumours (10 cases) had low labelling rates and all but one are still alive. We conclude that measurement of lung tumour growth rate with the monoclonal antibody Ki-67 shows promise as a possible indicator of short-term survival and perhaps as a means of choosing a group of patients with adenocarcinomas and squamous cell carcinomas for post-operative chemotherapy.

Twenty-eight carcinoid tumours were stained with monoclonal antibodies to epithelial and neural related intermediate filaments. All were found to express epithelial markers, and none expressed neural markers. These results support the theory that carcinoids are of epithelial, rather than neural crest origin.

We have evaluated the peripheral blood natural killer (NK) cell activity and the in vitro effect of recombinant gamma-interferon (r gamma-IFN) on NK cell activity in 23 patients with a neuroendocrine tumour of the pancreas, small intestine or liver, and 23 healthy controls. Patients with a gastrinoma showed a NK cell activity which was not different from that of the control group, whereas patients with another type of neuroendocrine tumour had a decreased NK cell activity compared to the controls (p less than 0.05) and the gastrinoma patients (p less than 0.02). The impaired NK cell activity in these patients was as such not related to the presence of liver metastasis or performance status of the patients. r gamma-IFN significantly stimulated the NK cell activity in patients and controls. However, the cytotoxic response of the patients with a hormone production other than gastrin remained lower than in the two other groups. Follow-up studies in 8 patients showed NK cell activities not to vary with stable disease, to decrease with progressive disease, and to increase with regression of disease. In conclusion, NK cell activity is suppressed in patients with neuroendocrine tumours that produce hormones other than gastrin. This impairment is not related to the presence of metastasis but seems to be related to the course of the disease.