| 1. |
- Fjällskog, Marie-Louise, et al.
(författare)
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Expression of somatostatin receptor subtypes 1 to 5 in tumor tissue and intratumoral vessels in malignant endocrine pancreatic tumors
- 2003
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Ingår i: Medical Oncology. - 1357-0560 .- 1559-131X. ; 20:1, s. 59-67
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Tidskriftsartikel (refereegranskat)abstract
- Somatostatin analogs are well established in the treatment of malignant endocrine pancreatic tumors (EPTs). Our goal is to individualize their treatment using receptor-subtype-specific analogs and, therefore, exploring the receptor expression is highly important. We have examined the expression of somatostatin receptor (sst) subtypes 1–5 on tumor cells and in intratumoral vessels in 28 tumor tissues from malignant EPTs with immunohistochemistry using sst-subtype-specific polyclonal antibodies. We found that sst2 and sst4 stained positive in 90% and sst1 in 70% of the tumor tissues, whereas sst3 and sst5 stained positive in only 50% of the tumor tissues. Sst expression in intratumoral vessels was high for sst2 and sst4 (80%), moderate for sst1 (40%), and low for sst3 and sst5 (10%). The ssts were evenly distributed among the different tumor subtypes. However, tumors belonging to the same subgroup of EPTs showed a variable expression of receptor subtypes. No differences in receptor-subtype expression could be seen between poorly and well-differentiated tumors, nor between primary tumors and metastases. Prior medical treatment did not influence sst expression pattern. In conclusion, sst2 and sst4 were expressed in most tumor tissues and intratumoral vessels from EPTs. However, sst3 and sst5 were lacking in half of the tumor tissues and in most of the intratumoral vessels. These differences indicate the importance of determining each tumor’s subset of receptors before treatment with receptor-subtype-specific analogs is initiated. The importance of sst expression in intratumoral vessels is not yet known.
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| 2. |
- Granberg, Dan, et al.
(författare)
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Clinical symptoms, hormone profiles, treatment, and prognosis in patients with gastric carcinoids
- 1998
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Ingår i: Gut. - : BMJ. - 0017-5749 .- 1468-3288. ; 43:2, s. 223-228
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Type 1 gastric carcinoids are associated with hypergastrinaemia and chronic atrophic gastritis, type 2 occur in patients with multiple endocrine neoplasia type 1 combined with Zollinger-Ellison syndrome, and type 3 lack any relation to hypergastrinaemia. Type 1 tumours are usually benign whereas type 3 are highly malignant. AIMS: To identify possible tumour markers in patients with gastric carcinoids. PATIENTS/METHOD: Nine patients with type 1, one with type 2, and five with type 3 were evaluated with regard to symptoms, hormone profile, and prognosis. RESULTS: Plasma chromogranin A was increased in all patients but was higher (p < 0.01) in those with type 3 than those with type 1 carcinoids. All patients with type 3 carcinoids died from metastatic disease, but none of the type 1 patients died as a result of their tumours. One type 1 patient with a solitary liver metastasis received interferon alpha and octreotide treatment. Nine months later, the metastasis was no longer detectable. She is still alive eight years after diagnosis, without recurrent disease. This represents the only reported case of foregut carcinoid with an unresectable liver metastasis that seems to be have been cured by biotherapy. CONCLUSIONS: Plasma chromogranin A appears to be a valuable tumour marker for all types of gastric carcinoid. Combination therapy with interferon alpha and octreotide may be beneficial in patients with metastasising type 1 gastric carcinoids.
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| 3. |
- Ludvigsen, Eva, et al.
(författare)
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Regulation of insulin and glucagon secretion from rat pancreatic islets in vitro by somatostatin analogues
- 2007
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Ingår i: Regulatory Peptides. - : Elsevier BV. - 0167-0115 .- 1873-1686. ; 138:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Somatostatin is an inhibitor of hormone secretion through specific receptors (sst1-5). The aim of this study was to investigate the putative regulatory role of somatostatin analogues on the secretion of insulin and glucagon by rat pancreatic islets. After 48 h exposure only the non-selective agonists (somatostatin, octreotide and SOM-230) inhibited insulin accumulation. The inhibition of insulin secretion was accompanied by increased islet insulin contents. None of the analogues showed a consistent effect on the glucagon accumulation in the medium after 48 h. Since we observed a difference in the regulatory effect between the non-selective and selective analogues, combinations of selective analogues were studied. Combination of sst2 + sst5 agonists inhibited the medium insulin accumulation, while combination of sst1 + sst2 analogues caused a decrease in glucagon accumulation. After removal of somatostatin a rebound effect with increased insulin secretion were observed. This effect was reversed after 6 h. For SOM-230 insulin secretion continued to be suppressed even after the analogue was removed and returned to control values after 3 h. As for glucagon secretion there was an initial decline after culture with octreotide, while the other substances failed to induce any changes. In summary, non-selective somatostatin analogues or combinations of receptor selective analogues may cause inhibition of hormone secretion from rat pancreatic islets. For insulin and glucagon, combinations of sst2 + sst5 and sst1 + sst2, respectively may exert this effects. Thus, our data suggest that more than one sst must be involved to down-regulate islet glucagon and insulin secretion.
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| 4. |
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| 5. |
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| 6. |
- Saras, Jan, et al.
(författare)
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Somatostatin induces rapid contraction of neuroendocrine cells
- 2007
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Ingår i: FEBS Letters. - : Wiley. - 0014-5793 .- 1873-3468. ; 581:10, s. 1957-1962
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Tidskriftsartikel (refereegranskat)abstract
- The peptide hormone somatostatin, as well as the somatostatin analog octreotide, induces rapid morphological changes in neuroendocrine cells. The effect can be detected in less than 2min: retraction fibers are formed, cells round up and cell–cell contacts are broken. Somatostatin-dependent cell contraction is inhibited by Y-27632, indicating that this effect is dependent on Rho kinase. In BON1 cells, the somatostatin-induced inhibition of forskolin-induced secretion of chromogranin A is not blocked by Y-27632. It is therefore concluded that the inhibitory effect of somatostatin in forskolin-stimulated cells is not dependent on cell contraction.
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| 7. |
- Stridsberg, Mats, et al.
(författare)
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Islet amyloid polypeptide (IAPP) in patients with neuroendocrine tumours
- 1995
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Ingår i: Regulatory Peptides. - 0167-0115 .- 1873-1686. ; 55:2, s. 119-131
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Tidskriftsartikel (refereegranskat)abstract
- Although IAPP was first discovered and isolated from amyloid deposits in an endocrine pancreatic tumour (EPT), surprisingly few reports have investigated the potential use of IAPP as a marker for neuroendocrine tumour growth. In this study we present results from plasma measurements of IAPP in 102 patients with neuroendocrine tumours. Four of 35 patients (11%) with midgut carcinoid tumours, but none of the patients (4 and 5, respectively) with lung carcinoids or with rectal carcinoids displayed elevated plasma levels of IAPP. Five of 31 patients (16%) with sporadic EPT and 3 of 27 patients (11%) with EPT and multiple endocrine neoplasia type 1 syndrome disclosed elevated IAPP levels. Within the different syndromes, 1/11 individuals with insulinoma, 2/16 with gastrinoma, 0/2 with glucagonoma, 0/3 with VIPoma and 5/26 with non-functioning tumours showed elevated plasma levels of IAPP. In two patients, the plasma IAPP levels were extremely elevated. These patients also exhibited altered glucose homeostasis. In response to a standardised mixed meal test, IAPP increased in parallel to the insulin, pancreatic polypeptide, gastrin and glucose responses. In MEN1 patients with hypercalcaemia due to increased secretion of parathyroid hormone, the plasma levels of IAPP were significantly higher before than after surgical removal of the parathyroid adenomas. However in normocalcaemic patients, no correlation between the blood calcium and plasma IAPP levels was found. Immunocytochemical staining of tumour tissue showed that 9/13 (69%) of insulin producing tumours, 4/14 (29%) of non-functioning tumours and 1/9 (11%) of gastrin producing tumours were IAPP immunoreactive. Amyloid deposits were always IAPP immunoreactive. In conclusion, increased circulating levels of IAPP occurred in 12% of 102 patients with neuroendocrine tumours. In 2 patients with extremely elevated plasma levels of IAPP, effects on glucose homeostasis were recorded. Thus, IAPP may be useful as an additional marker for neuroendocrine tumour growth in selected cases.
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| 8. |
- Tiensuu Janson, Eva, et al.
(författare)
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Carcinoid tumors : analysis of prognostic factors and survival in 301 patients from a referral center
- 1997
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Ingår i: Annals of Oncology. - 0923-7534 .- 1569-8041. ; 8:7, s. 685-690
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:Little is known about factors related to prognosis in patients with carcinoid disease. In this study we have tried to identify such factors.PATIENTS AND METHODS:We have evaluated 301 consecutive carcinoid patients (256 midgut, 39 foregut and six hindgut) referred during 15 years for medical treatment with respect to tumor distribution, hormone production, prognostic factors and survival.RESULTS:Survival was significantly shorter in midgut carcinoid patients with > or = 5 liver metastases or with high levels of urinary 5-hydroxyindoleacetic acid, plasma chromogranin A or neuropeptide K. By univariate analysis, these variables together with the presence of carcinoid syndrome were related to a higher risk of dying. In multivariate analyses, performed in the 71 patients with full information on all variables, advanced age and plasma chromogranin A > 5000 micrograms/l were independent predictors of overall survival.CONCLUSIONS:Poor prognostic factors for midgut carcinoid patients were multiple liver metastases, presence of carcinoid syndrome and high levels of the tumor markers studied. In this study the only independent predictors of bad prognosis in midgut, carcinoid patients were advanced age, which however is inherently related to overall survival, and plasma chromogranin A > 5000 micrograms/l. Thus, chromogranin A may prove to be an important prognostic marker for patients with carcinoid tumors.
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| 9. |
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| 10. |
- Welin, Staffan, et al.
(författare)
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Elevated Plasma Chromogranin A is the First Indication of Recurrence in Radically Operated Midgut Carcinoid Tumours
- 2009
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Ingår i: Neuroendocrinology. - : S. Karger AG. - 0028-3835 .- 1423-0194. ; 89:3, s. 302-307
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Tidskriftsartikel (refereegranskat)abstract
- Background:Patients with malignant midgut carcinoids are occasionally diagnosed with limited tumor spread, and surgery with radical intention is performed. Despite curative intent, recurrences occur frequently, motivating long-term biochemical and radiological follow-up. This study aimed to compare the usefulness of various methods in detecting such recurrences.Methods:This retrospective study included 56 patients with radically operated midgut carcinoids referred to our University Hospital for evaluation and follow-up between 1985 and 2004. Patients were monitored 1-3 times per year using plasma-chromogranin A (P-CgA), urinary 5-hydroxyindoleacetic acid (U-5HIAA) concentrations as well as radiological examinations, including ultrasonography, computerized tomography or magnetic resonance investigation. In a subset of cases, somatostatin receptor scintigraphy and/or positron emission tomography with 5-hydroxytryptophan was performed. Time from operation until established recurrence was recorded.Results:Tumor recurrence was established in 33 of 56 patients after a median of 32 months (range 6-217). Elevated P-CgA was the first marker to become pathologically elevated in 28 of these 33 patients (85%). In 3 of these 28 patients, radiology was simultaneously positive for a recurrence.Conclusion:P-CgA was the first marker to indicate tumor recurrence in the majority of radically operated midgut carcinoid patients. To avoid unnecessary and costly examinations in asymptomatic patients, we suggest that follow-up should comprise measurements of P-CgA twice a year and annual ultrasonography until P-CgA is elevated or clinical symptoms occur, at which time all efforts should be made to identify recurrent tumor lesions in order to give the patient the best possible treatment which, if possible, should be surgical removal of the recurrence.
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