[Gastroenteropancreatic neuroendocrine neoplasms. Role of biopsies]. / Neuroendokrine Neoplasien der Bauchspeicheldrüse und des Gastrointestinaltrakts. Was leistet die Biopsie?

Neuroendocrine neoplasms of the pancreas and the gastrointestinal tract are heterogeneous regarding etiology (e.g. sporadic or hereditary), histomorphology, hormone expression, hormone-related functional activity and especially the malignant potential. In neuroendocrine neoplasms the biopsy-based diagnosis plays an important role for the clinical management of patients. The diagnosis most importantly relies on the differentiation (e.g. organoid versus diffuse growth patterns) and the grading of tumors. The latter is based on the proliferation activity as determined by Ki-67 immunostaining and mitotic count and results in the current tumor classification into neuroendocrine tumors G1, neuroendocrine tumors G2 or neuroendocrine carcinomas G3. Occasionally, tumors may show mixed differentiation containing a non-neuroendocrine cancer component. The neuroendocrine markers synaptophysin and chromogranin A are recommended for the immunohistochemical confirmation of the diagnosis. Furthermore, biopsy material can be used to investigate the expression of therapy-related markers, such as somatostatin receptor-2A. Moreover, if needed, the expression of transcription factors and hormones can be determined to obtain information on the possible site of origin of metastatic neuroendocrine neoplasms or to determine the syndrome-inducing hormone in functionally active neuroendocrine neoplasms. Finally, using the stomach as an example, biopsies may also be successfully used to investigate neuroendocrine precursor lesions which may harbor prognostic significance.

A distinctive form of human chorionic gonadotropin beta-subunit-like material produced by cervical carcinoma cells.

The DoT and CaSki human cervical carcinoma cell lines ectopically produce material immunologically similar to the beta-subunit of human chorionic gonadotropin (hCG beta). Culture fluids were analyzed by gel filtration chromatography and radioimmunoassay (RIA) using (a) antiserum directed to conformation-specific (core-directed) determinants not involving the carboxyl-terminal peptide (CTP) in hCG beta purified from urinary hCG (i.e., standard hCG beta) or (b) antiserum directed to the CTP in standard hCG beta. CTP-directed RIA recognized a peak of hCG beta-like immunoreactive material that eluted in the same position as standard hCG beta. However, core-directed RIA recognized additional hCG beta-like material (i.e., ectopic beta-II), most of which eluted before standard hCG beta. CaSki cells were incubated with [3H]mannose, [3H]proline, and [3H] leucine, and the spent medium was immunoprecipitated and analyzed by gel electrophoresis. Several labeled peaks were detected in the lane from the anti-hCG beta X Sepharose immunoprecipitate, one of which corresponded in mobility to standard hCG beta, with two more intense components migrating at higher apparent molecular weights. Carboxypeptidase Y digestion released only 0.2 mol equivalents each of [3H]proline and [3H]leucine from the labeled CaSki material immunoprecipitated with anti-hCG beta X Sepharose, compared to 1 mol equivalent each in similar analysis of standard hCG beta. These findings were consistent with the absence of the 4-carboxy-terminal amino acids from 80% of the hCG beta-like immunoreactive material secreted by CaSki cells. The affinity purified ectopic beta-II failed to combine with standard hCG alpha under conditions in which combination of standard hCG beta with standard hCG alpha was essentially complete. Neither aggregation nor proteolytic degradation was the cause of failure of ectopic beta-II to combine with hCG alpha. We conclude that both the DoT and CaSki cervical carcinoma cell lines secrete a distinctive form of hCG beta-like material, ectopic beta-II. Lack of recognition by CTP-directed antisera and amino acid analysis suggest that ectopic beta-II may lack the CTP, despite its apparent larger size relative to standard hCG beta.

Serum resistin levels of obese and lean children and adolescents: biochemical analysis and clinical relevance.

OBJECTIVE: It was hypothesized that resistin links obesity with diabetes, but this has not been studied in children and adolescents to date. PATIENTS: We determined serum resistin levels of 135 obese (body mass index, 32.0 +/- 6.2 kg/m2; age, 12.6 +/- 3.4 yr) and 201 lean children (body mass index, 18.7 +/- 2.4 kg/m2; age, 12.5 +/- 2.5 yr) by a newly developed and extensively evaluated in-house immunoassay. These results were controlled for their association with markers of puberty, obesity, and insulin sensitivity. RESULTS: The analytical evaluation of our assay revealed different resistin isoforms with major peaks of higher than 660 and 55 kDa in the size exclusion chromatography. Using this assay system we found no difference in the resistin levels of obese compared with lean subjects (P = 0.48). However, resistin was significantly higher in girls than in boys (6.74 +/- 2.42 vs. 5.79 +/- 2.45; P < 0.001). Interestingly, in both obese and lean children, resistin correlated with age (P < 0.01), Tanner stage, and testosterone and estradiol levels (P < 0.05). In contrast, no significant correlation was found with parameters of insulin resistance such as homeostasis model assessment, insulin sensitivity index, or insulin, proinsulin, and glucose concentrations in obese subjects. CONCLUSIONS: Resistin appears to be not the main link between obesity and insulin resistance in children and adolescents but because of its association with Tanner stage, it may be related to the maturation of children during pubertal development. Additionally, we have demonstrated the presence of different molecular isoforms of resistin in human blood, and this may raise problems in comparing data from diverse assay systems.

Stimulated resistin expression in white adipose of rats with bile duct ligation-induced liver cirrhosis: relationship to cirrhotic hyperinsulinemia and increased tumor necrosis factor-alpha.

Resistin, an adipose-derived polypeptide hormone, is proposed as a candidate of insulin resistance, although its roles in inhibiting adipogenesis and in inflammation have also been suggested. Liver cirrhosis is characterized by elevated circulating proinflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha), hyperinsulinemia and insulin resistance. The study aimed to examine resistin expression and its association with insulin and TNF-alpha in a cirrhotic rat model using bile duct ligation (BDL). The BDL-induced cirrhotic rats showed significantly lower fat mass, insulin sensitivity and elevated plasma insulin and TNF-alpha compared to sham animals. In addition, epididymal TNF-alpha and resistin mRNA and protein levels were higher in cirrhotic rats. In normal control rats, in vivo insulin infusion and ex vivo administration of TNF-alpha to cultured fat pads increased resistin gene expression significantly. These results implied that hyperinsulinemia and increased TNF-alpha levels might upregulate adipose resistin gene in BDL-induced liver cirrhosis. Further study is necessary to document the role of resistin in metabolic abnormalities of liver cirrhosis.

Changes in glycemia by leptin administration or high- fat feeding in rodent models of obesity/type 2 diabetes suggest a link between resistin expression and control of glucose homeostasis.

Resistin is an adipose-derived hormone that has been proposed as a link among obesity, insulin resistance, and diabetes. In agreement with a role of resistin in insulin resistance, the administration of recombinant resistin led to glucose intolerance in mice and impaired insulin action in rat liver. However, the regulation of resistin expression by physiological conditions, hormones, or agents known to modulate insulin sensitivity does not always support the association between resistin and obesity-induced insulin resistance. In the present study we investigated the effects of leptin administration on adipose resistin expression in insulin-resistant and obese ob/ob mice. We show that the expression of resistin mRNA and protein in adipose tissue is lower in ob/ob than in wild-type control mice, in agreement with the reduced adipocyte resistin mRNA level reported in several models of obesity. Leptin administration in ob/ob mice resulted in improvement of insulin sensitivity concomitant with a decrease in resistin gene expression. The lack of effect of leptin on resistin in db/db mice indicated that the leptin inhibitory action on resistin expression requires the long leptin receptor isoform. In addition, we demonstrated that the effect of leptin on resistin expression was centrally mediated. High-fat feeding in C57BL/6J wild-type mice, which is known to induce the development of obesity and insulin resistance, produced an increase in resistin expression. Interestingly, in both ob/ob and high fat-fed mice we obtained a striking positive correlation between glycemia and resistin gene expression. In conclusion, our results demonstrate that leptin decreases resistin expression and suggest that resistin may influence glucose homeostasis.

Resistin is expressed in the human placenta.

The mechanism for decreased insulin sensitivity in pregnant women is not fully clarified. Resistin, a novel peptide hormone, is specifically expressed in the adipose tissue and decreases insulin sensitivity in rodents. In the present study, we demonstrate resistin gene expression in the human placental tissue, mainly in trophoblastic cells. The resistin gene expression in term placental tissue was more prominent than was seen in the first trimester chorionic tissue. In contrast resistin gene expression in adipose tissue was rather weak and remained unchanged by pregnancy. Thus, resistin is a newly isolated placental hormone in humans which may modulate insulin sensitivity during pregnancy.

Resistin promotes 3T3-L1 preadipocyte differentiation.

OBJECTIVE: To investigate the relationship between resistin (a potential link between obesity and type 2 diabetes) and preadipocyte differentiation. DESIGN: A rat resistin expression vector was transfected into 3T3-L1 preadipocytes and differentiation was compared between normal 3T3-L1 cells, rat resistin-transfected cells and non-transfected cells grown in conditioned medium taken from resistin-expressing cultures. METHODS: The rat resistin gene was inserted into the pDual GC and pEFGP-N2 expression vectors for examination of the effects of resistin overexpression in 3T3-L1 cells before and after differentiation was stimulated with 3-isobutyl-1-methyxanthine (MIX), insulin and dexamethasone (DEX). Smaller conserved fragments were inserted into short interference RNA (siRNA) expression vectors, for examination of the effect of targeted resistin inhibition on differentiation of resistin-overexpressing 3T3-L1 cells. RESULTS: Prior to stimulation, the resistin-transfected 3T3-L1 cells contained many more small lipid droplets than did non-transfected 3T3-L1 cells. Following stimulation, differentiation in the resistin-transfected 3T3-L1 cells was dramatically promoted, especially in the early stages. Stimulation of differentiation was also observed in non-transfected 3T3-L1 cells grown in resistin protein-containing conditioned medium. The expression of adipocyte differentiation-associated markers such as CCAAT enhancer binding protein (C/EBPalpha), retinoid X receptor (RXRalpha) and lipoprotein lipase (LPL) was upregulated in resistin-overexpressing cells, whereas expression of preadipocyte factor-1 (Pref-1), an inhibitor of preadipocyte differentiation, was downregulated. In addition, expression of two of the three tested siRNAs inhibited the adipoconversion process, providing further evidence that resistin promotes the differentiation of preadipocytes to adipocytes. CONCLUSION: Resistin can promote preadipocyte differentiation. Based on this, we propose that resistin may be an important candidate mediator of obesity-induced insulin resistance.

Predictive testing of radiosensitivity in non-small cell carcinoma of the lung.

The paper reviews the prognostic factors which influence the radiosensitivity of non-small cell lung cancer. The clonogenic cell numbers, hypoxic fraction, tumour cell kinetics and inherent radiosensitivity are considered. In the future the measurement of these factors may play an important role in decision making as to the best management for patients with non-small cell lung cancer.

Immunocytochemical demonstration of growth hormone-releasing factor in gastrointestinal and pancreatic endocrine tumors.

Growth hormone-releasing factor (GRF), a linear peptide that exists in a number of different molecular forms (GRF-44, -40, -37, and-31) has been shown to be responsible for the acromegaly associated with certain endocrine tumors of the pancreas and other foregut-derived structures. With the use of two anti-sera (#1A850 and G59/901) directed against different segments of the GRF molecule, a series of 24 pancreatic and 35 gastrointestinal endocrine tumors, not associated with acromegaly, were surveyed systematically for immunocytochemical localization of GRF in the tumor cells. Strong immunoreactivity for GRF was encountered in 10 tumors (6 pancreatic and 4 gastrointestinal). While all ten tumors were immunoreactive against G59/901, which recognizes GRF-44, -40, and -37, two jejunal carcinoids showed additional immunostaining with 1A850 that is specific for GRF-44. Seven of these ten tumors were also immunoreactive for a variety of other regulatory peptides and neurotransmitters, including gastrin, insulin, glucagon, serotonin, substance P, somatostatin, pancreatic polypeptide, vasoactive intestinal peptide (VIP), and adrenocorticotropic hormone (ACTH). No consistent pattern of association between GRF and the other regulatory substances was evident. These findings indicate that, even in the absence of associated acromegaly, up to 17% of endocrine tumors of the gastro-entero-pancreatic (GEP) axis show immunoreactivity for GRF and that such reactivity is associated more frequently with pancreatic (25%) than with gastrointestinal (11%) endocrine tumors.

Prostatic carcinoma with endocrine features. A report of a neoplasm containing multiple immunoreactive hormonal substances.

A case of prostatic carcinoma with the cellular patterns of an adenocarcinoma and carcinoid tumor is reported. The tumor contained ultrastructural dense core neuroendocrine granules, and immunoperoxidase staining revealed prostatic acid phosphatase, prostatic-specific antigen, chromogranin, neuron-specific enolase, serotonin, adrenocorticotrophic hormone (ACTH), somatostatin, parathormone, calcitonin, bombesin, and glucagon but no insulin. The patient had exhibited hypercalcemia that may have been related to hormone production by the tumor. The literature on the endocrine aspect of the prostate and its tumor is reviewed.

Somatostatin and adrenocorticotrophic hormone like immunoreactivity in small cell carcinoma of the lung.

The immunocytological detection of adrenocorticotrophic hormone (ACTH) and somatotropin release inhibitor factor (SRIF) like immunoreactivity was carried out on tumour cells from bronchial brush smears in 39 cases of lung tumours. Results obtained were compared with the cytological and histological diagnosis and confirmed the high incidence of ACTH synthesis by malignant bronchial carcinoma cells: the same phenomenon also seems to occur for somatostatin. The concomitant detection of ACTH and SRIF like immunoreactivity seems to be highly suggestive of small cell carcinoma and indicates that the immunocytological detection of hormones carried out at the same time as cytological examination can improve the accuracy of the diagnosis.

Simultaneous ectopic production of parathyroid hormone and calcitonin.

Two patients with cancer were evaluated in whom there was evidence for the simultaneous ectopic production of parathyroid hormone (PTH) and calcitonin (CT). One patient had a gastric carcinoid and the other had a pancreatic islet cell carcinoma. Abnormal concentrations of parathyroid hormone and calcitonin were demonstrated by radioimmunoassay in the peripheral blood of each patient and in the gastric tumor. In the pancreatic tumor, immunohistologic studies also demonstrated the presence of CT and PTH and suggested that each hormone was produced by different cells of the tumor. Plasma concentrations of the hormones responded to functional tests of secretion and to tumor chemotherapy. These studies demonstrate the simultaneous ectopic production of the two physiologically antagonistic hormones, PTH and CT, and confirm their value as diagnostic markers for several types of malignancies.

Immunohistochemical localization and chromatographic characterization of human chorionic gonadotropin in a bladder carcinoma.

We describe a patient with advanced bladder carcinoma, in which ectopic synthesis and secretion of human chorionic gonadotropinlike immunoreactivity (ihCG) was demonstrated. Concanavalin A-sepharose affinity chromatography of serum revealed that the ihCG differed from placental human chorionic gonadotropin in its carbohydrate moiety. Treatment of the patient with a cisplatin-containing regimen did not result in regression of the tumor. Since immunohistochemistry revealed ihCG in five of 13 additional cases of bladder carcinoma, it is concluded that ectopic production of ihCG by bladder carcinomas is probably not rare.

New horizons in hCG detection.

The advent of high technology in the field of hCG measurement has created a greater requirement for high expertise in the analysis and evaluation of hCG levels, particularly low-positive levels, and for the concomitant clinical management of the patient. This implies an imperative to treat trophoblastic disease patients in trophoblast disease referral centers.

The carbohydrate on human chorionic gonadotropin produced by cancer cells.

Using the methods described, it is not possible to determine the number of N- and O-linked oligosaccharides on ectopic hCG beta. On standard hCG beta there are two NeuAc residues on each N- and O-linked oligosaccharide, so that the number of NeuAc residues is proportional to the number of oligosaccharides. Ectopic hCG beta and desialylated ectopic hCG beta are of similar molecular size to the standard preparations (gel filtration and RIA with anti-CTP antisera, data not presented). This suggests that ectopic hCG beta is sialylated to a similar extent as standard hCG beta, so the number of oligosaccharides on ectopic hCG beta could be similar to the number on standard hCG beta. There is a Fuc attached to the N-linked oligosaccharides of standard hCG beta (Fig. 3). Using the methods described, it was not possible to determine if this residue is also found on the N-linked oligosaccharides of ectopic hCG beta. Recently, a second form of ectopic hCG beta was identified (22). This form lacks the characteristic hCG beta carboxyterminal peptide, and as such is unrecognized by the RIA used in this study. Like the ectopic hCG beta described herein, and that produced by other cancers, this molecule only partially binds to Con A, and binds to Ricinus communis-120 following neuraminidase digestion. Intact hCG and free hCG subunits, which only partially bind to Con A, are found in cancer tissues, cancer sera, and the medium of cultured trophoblastic and nontrophoblastic cancer cells (Table 1). Our studies with DoT cancer of the cervix cells clearly indicate that the partial binding could be the consequence of the linkage of extra beta G1cNAc residues.

A rare case of ectopic antidiuretic hormone-producing pancreatic adenocarcinoma: new diagnostic approach.

We describe a 73-year old man with the syndrome of inappropriate antidiuretic hormone secretion (SIADH) due to an ectopic ADH-producing pancreatic adenocarcinoma. His laboratory findings showed marked hyponatremia, and the water load test showed uncontrolled ADH secretion. The imaging studies revealed pancreatic body cancer. Histological examination revealed an adenocarcinoma of the pancreas, which was positive for ADH immuno-staining. The ADH in the tumor extract was 53.3 pg/g wet weight. In attempt to diagnose ADH-production from the tumor, the ADH in his pancreatic juice was measured and found to be 2.1 pg/ml. We conclude that it is valid to measure the ADH in pancreatic juice to diagnose ectopic ADH production by tumors.

Cytologic and hormonal findings in a carcinoid tumor of the uterine cervix.

A carcinoid tumor of the cervix in a 40-year-old woman was studied by cytology, histology, electron microscopy, immunohistochemistry and hormonal analysis. The preoperative cytologic and histologic findings strongly suggested a carcinoid tumor of the cervix. The serum serotonin level was elevated; immunohistochemical studies demonstrated the presence of serotonin in the cytoplasm of the tumor cells. Following radical hysterectomy, the concentration of serotonin was measured in the excised tumor; it was about 20 times higher than the level seen in normal cervical tissue, confirming that the tumor was a serotonin-secreting carcinoid of the uterine cervix.

Molar pregnancy of hyperthyroidism.

A report on a patient with clinical hyperthyroidism associated with hydatidiform mole is presented. Some biochemical characteristics of the thyroid stimulator isolated from the tumour are discussed.

[Ectopic hormone producing cells in non-small cell lung carcinoma (non-SCLC) and heterogeneity of lung cancer].

68 cases of non-SCLG were investigated by immunohisto-chemical technique to detect ectopic hormone producing cells and to study the heterogeneity of non-SCLC. Histologic heterogeneity was observed in 11 of 68 non-SCLC and 24 (35.3%) cases displayed hormone immunoreactivity. Ten cases were positive for NSE. More than one type of hormone producing cells could be detected in 11 tumors. Both neutral and acid mucoproteins in variable quantities were observed in 17 tumors that contained the hormone or NSE producing cells. The results indicate that there is functional heterogeneity in non-SCLC, and all types of lung carcinoma may have a common cellular origin.

Ectopic hormones--biochemical aspects.

Biochemical evidence suggests that ectopic hormone production is much more common than suspected clinically. The majority of lung carcinomas of oat cell or carcinoid type appear to synthesise ACTH and related peptides, calcitonin and less frequently, chorionic gonadotrophin and vasopressin. The primary amino acid sequences of ectopic hormones closely resemble their normal counterparts but ectopic hormone producing tumours contain greater proportions of high molecular weight, subunit and fragment forms than the normal gland of origin. Assays for ectopic hormones are clinically useful in diagnosis, tumour localisation, and monitoring patients with ectopic hormonal syndromes. Currently the clinical value of hormone assays in the routine management of common forms of malignancy in the absence of overt ectopic hormonal syndromes is unproven. However, better characterisation of hormonal forms relatively specific for neoplasia together with improved assay specificity and sensitivity may enhance the clinical value of ectopic hormones as tumour markers, particularly in malignancies which are commonly associated with ectopic hormone production (e.g. lung cancer).