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- 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. |
- Welin, Staffan, et al.
(författare)
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Expression of tyrosine kinase receptors in malignant midgut carcinoid tumors
- 2006
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Ingår i: Neuroendocrinology. - : S. Karger AG. - 0028-3835 .- 1423-0194. ; 84:1, s. 42-48
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Tidskriftsartikel (refereegranskat)abstract
- Background: The expression of certain tyrosine kinase receptors (TKR) has been shown to have a prognostic value in many tumor entities. In recent years, inhibitors and monoclonal antibodies directed towards these receptors have been developed. Several have shown antitumoral effects and have been tested in clinical trials. We wanted to investigate whether midgut carcinoid tumors express TKR and therefore would be suitable for clinical trials with TKR inhibitors (TKRI) or monoclonal antibodies. Material and Methods: Tumor tissue from 36 patients (24 women and 12 men) with a malignant midgut carcinoid tumor was obtained. The tissues were examined with immunohistochemistry, using polyclonal antibodies against platelet-derived growth factor receptor-α (PDGFRα), platelet-derived growth factor receptor-β (PDGFRβ), epidermal growth factor receptor (EGFR) and c-kit. Human BON1 cells were cultivated and stimulated with PDGF-BB. We also present a case report of a patient with a malignant midgut carcinoid tumor who had stabilization of tumor growth during treatment with imatinib. Results: Immunohistochemical staining for PDGFRα in tumor cells showed immunoreaction for the receptor in 13/34 (38%) for PDGFRβ in 29/33 (88%), and 24/33 (73%) were immunoreactive for EGFR. No tumor tissue showed immunoreaction for c-kit. In tumor stroma PDGFRα was expressed in 35%, PDGFRβ in 94% and EGFR in 9%. We show that human neuroendocrine tumor cells respond to PDGF, indicating that these tumors express functional PDGF receptors. Conclusion: Malignant midgut carcinoid tumors may express three of the four TKR tested in this investigation. Therefore, these tumors might be susceptible for treatment with TKRI or monoclonal antibodies and this should be further explored in clinical trials.
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