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Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although radiography, computed tomography and magnetic resonance imaging are still the methods of choice for the study of lung cancer, they have certain limitations in the determination of the nature of suspicious lung nodules, the evaluation of mediastinal involvement, the assessment of the viability of previously treated lesions and the diagnosis of tumour relapse. There is a wide range of current oncological requirements related to lung cancer: detection of malignant lesions at the earliest stage and in the most effective way; the definition of the biological characteristics of a lesion (proliferation, aggressiveness, differentiation, etc.); the need to define the operability of the patient (function of residual lung and staging); and the need to evaluate the behaviour of the tumour (response to therapy, early detection of recurrences, metastatic spread). Most of the efforts of the nuclear medicine community have been focussed on diagnosis, staging, restaging and therapy monitoring of lung cancer. Many radiopharmaceuticals have been employed for this, including gallium, monoclonal antibodies, somatostatin analogues, lipophilic cations and positron emission tracers. There is ample evidence that nuclear medicine techniques may provide complementary information with respect to anatomical imaging, for example in the assessment of preoperative function by means of ventilation and perfusion scintigraphy, or in tumour localisation by means of specific tumour-seeking agents. However, clinical data suggest that, when properly used, nuclear medicine procedures in some cases may be not only complementary to radiology but essential for the clinical management of lung cancer. An example of such a procedure is fluorodeoxyglucose positron emission tomography (FDG PET) the introduction of which has greatly contributed to confirmation of the clinical value of nuclear medicine in this field. FDG PET has proved of great help in lung cancer management and its cost-effectiveness in lung cancer staging is firmly established. In this review the results of the most important nuclear medicine techniques are summarised and their value in clinical practice is discussed. General, updated information is provided about the epidemiology, biology and clinical management of lung cancer, and about the role of nuclear medicine in these areas.
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PMID:Nuclear medicine procedures in lung cancer. 1038 99

The authors report that 4 out of a series of 56 patients (7.1%) treated with gemcitabine developed an unexplained non-cardiogenic pulmonary distress syndrome most likely related to gemcitabine. One further patient developed ventricular arrhythmia immediately after gemcitabine exposure, leading to cardiac arrest. Between 1995 and 1998 56 patients with locally advanced or metastatic carcinoma were treated with gemcitabine. The patients suffered from breast cancer (n = 17), pancreatic cancer (n = 17), lung cancer (n = 12), cancer of unknown primary (n = 5), ovarian cancer (n = 2), oral cavity cancer (n = 2) and cancer of the bladder (n = 1). Their median age was 55 years, and there were 33 female and 23 male patients. Fifteen patients had been pretreated with radiation therapy: 2 had received radiation therapy involving the mediastinum as treatment for non-small-cell lung cancer and cancer of unknown origin respectively, 11 patients had had prior neoadjuvant or adjuvant radiation therapy of the chest wall for breast cancer and 2 patients had received radiation therapy for head/neck cancer. All patients received gemcitabine on days 1, 8 and 15 and this was repeated on day 29 at a dose of 1000 mg/m(2) as a 30-min infusion in 250 ml isotonic NaCl. In 4 patients gemcitabine treatment was combined with cisplatinum, in 7 patients with a somatostatin analogue and in 1 patient with epirubicin. All other patients received gemcitabine as a single agent. We assume that the pulmonary or cardiac toxicity of 5 patients was related to gemcitabine. In 3 patients re-exposure resulted in repeated toxicity. One patient did not receive gemcitabine again because of the life-threatening nature of the primary response. Two patients had received prior radiation to the mediastinum with 62 Gy and 50 Gy respectively, 3 years and 1 year before gemcitabine application. In our experience pulmonary toxicity after gemcitabine treatment is more common than initially anticipated. Gemcitabine should be used with caution in patients who have received prior radiation to the mediastinum.
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PMID:Severe non-haematological toxicity after treatment with gemcitabine. 1054 71

Regulatory peptides are small, readily diffusable and potent natural substances with a wide spectrum of receptor-mediated actions in humans. High affinity receptors for these peptides are (over-) expressed in many neoplasms, and these receptors may represent, therefore, new molecular targets for cancer diagnosis and therapy. This review intends to give an overview of the peptide-based radiopharmaceuticals which are presently already commercially available or which are in advanced stages of their clinical testing so that their broader availability is anticipated soon. Physiologically, these peptides bind to and act through G protein-coupled receptors in the cell membrane. Historically, somatostatin analogs are the first class of receptor binding peptides having gained clinical application. 111In-DTPA-[D-Phe1]-octreotide is the first and only radiopeptide which has obtained regulatory approval in Europe and the United States to date. Extensive clinical studies involving several thousands of patients have shown that the major clinical application of somatostatin receptor scintigraphy is the detection and the staging of gastroenteropancreatic neuroendocrine tumors (carcinoids). In these tumors, octreotide scintigraphy is superior to any other staging method. However, its sensitivity and accuracy in other, more frequent neoplasms is limited. Radiolabeled vasoactive intestinal peptide (VIP) has been shown to visualize the majority of gastrointestinal adenocarcinomas, as well as some neuroendocrine tumors, including insulinomas (the latter being often missed by somatostatin receptor scintigraphy). Due to the outstanding diagnostic accuracy of the pentagastrin test in detecting the presence, persistence, or recurrence of medullary thyroid cancer (MTC), we postulated the expression of the corresponding [i.e., cholecystokinin (CCK-)-B] receptor type in human MTC. This receptor is also widely expressed on human small-cell lung cancer. Indeed, 111In-labeled DTPA derivatives of gastrin showed excellent targeting of CCK-B receptor expressing tissues in animals and patients. A variety of further peptide-based radioligands is currently under development. Summarizing, radiolabeled regulatory peptides have opened new horizons in nuclear oncology for diagnosis (and potential internal radionuclide therapy). Further work will probably reveal a multitude of novel potentially clinically useful peptide-based radioligands.
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PMID:Diagnostic applications of radiolabeled peptides in nuclear endocrinology. 1056 42

The effects of prostaglandin E2 (PGE2) and vasoactive intestinal peptide (VIP) on vascular endothelial cell growth factor (VEGF) mRNAs were investigated using lung cancer cells. By RT-PCR, VEGF(121), VEGF(165), and VEGF(189), but not VEGF(206) isoforms were detected in all lung cancer cell lines and biopsy specimens examined. By Northern blot, VEGF mRNA was detected in all small cell lung cancer (SCLC) and non-SCLC (NSCLC) cell lines examined. PGE2, VIP and forskolin caused increased VEGF expression in a time- and concentration-dependent manner using NSCLC cell line NCI-H157. Approximately 1 microM PGE2, 0.1 microM VIP and 50 microM forskolin caused cAMP elevation, 64-, 33- and 128-fold, respectively, using NCI-H157 cells after 5 min. The increase in cAMP caused by PGE(2) and VIP was reversed by somatostatin (SST). Also 1 microM PGE2, 0.1 microM VIP and 50 microM forskolin increased the VEGF mRNA 2.0-, 1.5- and 2.3-fold, respectively, after 4 h. The increase in VEGF mRNA caused by PGE2, VIP and forskolin was inhibited by H-89, a protein kinase A inhibitor. A VIP receptor antagonist, VIPhybrid, inhibited the increase in cAMP and VEGF mRNA caused by VIP. By ELISA, VEGF was detected in the conditioned media exposed to the lung cancer cell lines. These results suggest that VEGF synthesis in and secretion from lung cancer cells can be regulated by agents, which cause adenylyl cyclase activation.
Lung Cancer
PMID:Prostaglandin E2 and vasoactive intestinal peptide increase vascular endothelial cell growth factor mRNAs in lung cancer cells. 1116 99

Despite developments in diagnosis and treatment, lung cancer is the commonest cause of cancer death in Europe and North America. Due to increasing cigarette consumption, the incidence of the disease and resultant mortality is rising dramatically in women. Novel approaches to the management of lung cancer are urgently required. Somatostatin is a tetradecapeptide first identified in the pituitary and subsequently throughout the body particularly in neuroendocrine cells of the pancreas and gastrointestinal tract and the nervous system. The peptide has numerous functions including inhibition of hormone release, immunomodulation and neurotransmission and is an endogenous inhibitor of cell proliferation and angiogenesis. Somatostatin and its analogs, including octreotide (SMS 201-995), somatuline (BIM 23014) and vapreotide (RC-160), act by binding to specific somatostatin receptors (SSTR) of which there are 5 principal subtypes, SSTR-1-5. Although elevated plasma somatostatin levels may be detected in 14-15% of patients, tumor cell expression appears rare. SSTR may be expressed by lung tumors, particularly small cell lung cancer and bronchial carcinoid disease. [(111)In]pentetreotide scintigraphy may have a role to play in the localization and staging of lung cancers both before and following treatment, and in detecting relapsed disease. The potential role of radiolabelled somatostatin analogs as radiotherapeutic agents in the management of lung cancer is currently being explored. Somatostatin analog therapy results in significant growth inhibition of both SSTR-positive and SSTR-negative lung tumors in vivo. Recent work indicates that these agents may enhance the efficacy of chemotherapeutic agents in the treatment of solid tumors including lung cancer.
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PMID:Somatostatin, its receptors and analogs, in lung cancer. 1127 4

Regulatory peptides are small, readily diffusable and potent natural substances with a wide spectrum of receptor-mediated actions in humans. High affinity receptors for these peptides are (over-) expressed in many neoplasms, and these receptors may represent, therefore, new molecular targets for cancer diagnosis and therapy. This review aims to give an overview of the peptide-based radiopharmaceuticals which are presently already commercially available or which are in advanced stages of their clinical testing so that their broader availability is anticipated soon. Physiologically, these peptides bind to and act through G protein-coupled receptors in the cell membrane. Historically, somatostatin analogs are the first class of receptor binding peptides having gained clinical application. 111In-DTPA-[D-Phe1]-octreotide is the first and only radiopeptide which has obtained regulatory approval in Europe and the United States to date. Extensive clinical studies involving several thousands of patients have shown that the major clinical application of somatostatin receptor scintigraphy is the detection and the staging of gastroenteropancreatic neuroendocrine tumors (carcinoids). In these tumors, octreotide scintigraphy is superior to any other staging method. However, its sensitivity and accuracy in other, more frequent neoplasms is limited. Radiolabeled vasoactive intestinal peptide (VIP) has been shown to visualize the majority of gastrointestinal adenocarcinomas, as well as some neuroendocrine tumors, including insulinomas (the latter being often missed by somatostatin receptor scintigraphy). Due to the outstanding diagnostic accuracy of the pentagastrin test in detecting the presence, persistence, or recurrence of medullary thyroid cancer (MTC), we postulated the expression of the corresponding (ie. cholecystokinin [CCK-] -B) receptor type in human MTC. This receptor is also widely expressed on human small-cell lung cancer. Indeed, 111In-labeled DTPA derivatives of gastrin showed excellent targeting of CCK-B receptor expressing tissues in animals and patients. A variety of further peptide-based radioligands, e.g. among many others, gastrin-releasing peptide/bombesin, neurotensin, substance-P, pan-somatostatin (somatostatin derivatives which bind to all five receptor subtypes) or glucagon-like peptide-1 (glp-1) analogs (the latter for the specific detection of insulinomas), is currently under development. Summarizing, radiolabeled regulatory peptides have opened new horizons in nuclear oncology for diagnosis (and potential internal radionuclide therapy). Future work will probably reveal a multitude of novel potentially clinically useful peptide-based radioligands.
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PMID:Imaging tumors with peptide-based radioligands. 1147 70

Several tumors overexpress somatostatin receptors (SSTR) and can thus be imaged with radiolabeled analogues of somatostatin. Tc-99m depreotide is a new radiolabeled somatostatin analogue that shows high affinity for SSTR2, SSTR3, and SSTR5 subtypes. It has been recently FDA-approved for use in the evaluation of indeterminate solitary pulmonary nodules. SPECT with Tc-99m depreotide is highly accurate in this clinical setting and may be preferable to FDG-PET because of its lower cost and wider availability. Large studies are also underway to evaluate the accuracy of Tc-99m depreotide in staging of lung cancer.
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PMID:Somatostatin receptor imaging of non-small cell lung cancer with 99mTc depreotide. 1196 4

The high-level expression of somatostatin receptors (SSTR) on various tumor cells has provided the molecular basis for successful use of radiolabeled peptide analogues as tumor tracers in nuclear medicine. The vast majority of human tumors seem to overexpress one or the other of 5 distinct hSSTR subtype receptors. Whereas neuroendocrine tumors frequently overexpress human(h) SSTR2, intestinal adenocarcinomas frequently express hSSTR3 or hSSTR4, or both of these hSSTRs. In contrast to (111)In-diethylenetriamine pentaacetic acid (DTPA)-(D)he(1)-octreotide (OctreoScan; Mallinckrodt, Petten, NL), which binds to hSSTR2 and 5 with high affinity (K(d)0.1-5 nmol/L), to hSSTR3 with moderate affinity (K(d)10-100 nmol/L), and does not bind to hSSTR1 and hSSTR4, (111)In /(90)Y-DOTA-lanreotide was found to bind to hSSTR2, 3, 4, and 5 with high affinity, and to hSSTR1 with lower affinity (K(d)200 nmol/L). Based on its unique hSSTR binding profile, (111)In-DOTA-lanreotide was suggested to be a potential radioligand for tumor diagnosis, and (90)Y-DOTA-lanreotide suitable for receptor-mediated radionuclide therapy. When directly compared with (111)In-DTPA-(D)he(1)-octreotide and (111)In-DOTA-(D)he(1)-Tyr(3)-octreotide, discrepancies in the scintigraphic imaging pattern are seen in about one third of tumor patients concerning both the tumor uptake as well as the detection of tumor lesions. On a molecular level, these discrepancies seem to be based on a higher high-affinity binding affinity of (111)In-DOTA-(D)he(1)-Tyr(3)-octreotide for hSSTR2 (K(d)0.1-1 nmol/L). Beneficial results of receptor-mediated experimental radionuclide therapy were first reported for high-dose treatment with (111)In-DTPA-(D)he(1)-octreotide, based on the emission of Auger electrons. Phase IIa of the Multicenter Analysis of a Universal Receptor Imaging and Treatment Initiative, a European Study (MAURITIUS), shows in progressive cancer patients (therapy entry criteria) with a calculated tumor dose > 10 Gy/GBq (90)Y-DOTA-lanreotide, the proof-of-principle for treating tumor patients with peptide receptor imaging agents. In the MAURITIUS study, cumulative treatment doses up to 232 mCi (90)Y-DOTA-lanreotide were given as short-term intravenous infusion. Preliminary treatment results in 154 patients indicate stable tumor disease in 41% (63 of 154) of patients and regressive tumor disease in 14% (22 of 154) of tumor patients with different tumor entities expressing hSSTR. No severe acute or chronic hematologic toxicity, change in renal or liver function parameters caused by (90)Y-DOTA-lanreotide treatment were reported for patients in the MAURITIUS trial. In two thirds of patients with neuroendocrine tumor lesions, (90)Y-DOTA-(D)he(1)-Tyr(3)-octreotide showed a higher tumor uptake and should therefore be considered the first choice for experimental receptor-based therapy. Potential indications for (90)Y-DOTA-lanreotide treatment are radioiodine-negative thyroid cancer, hepatocellular cancer, lung cancer, some brain tumors, and possibly melanomas. In conclusion, preclinical data and clinical studies confirm the potential usefulness of radiolabeled lanreotide for tumor diagnosis and therapy. However, careful consideration of the type of radiotracer used for receptor-mediated therapy should be made for the individual patient. Whole-body dosimetry should always be performed to predict doses for tumors and the critical organs, which are kidney and bone marrow.
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PMID:In- and Y-DOTA-lanreotide: results and implications of the MAURITIUS trial. 1196 10

The high level expression of somatostatin receptors (SSTR) on various tumor cells has provided the molecular basis for successful use of radiolabeled octreotide / lanreotide analogs as tumor tracers in nuclear medicine. Other (nontumoral) potential indications for SSTR scintigraphy are based on an increased lymphocyte binding at sites of inflammatory or immunologic diseases such as thyroid-associated ophthalmology. The vast majority of human tumors seem to over-express the one or the other of five distinct hSSTR subtype receptors. Whereas neuroendocrine tumors frequently overexpress hSSTR2, intestinal adenocarcinomas seem to overexpress more often hSSTR3 or hSSTR4, or both of these hSSTR. In contrast to In-DTPA-DPhe(1)-octreotide (OctreoScan(R)) which binds to hSSTR2 and 5 with high affinity (Kd 0.1-5 nM), to hSSTR3 with moderate affinity (K(d) 10-100 nM) and does not bind to hSSTR1 and hSSTR4, (111)In / (90)Y-DOTA-lanreotide was found to bind to hSSTR2, 3, 4, and 5 with high affinity, and to hSSTR1 with lower affinity (K(d) 200 nM). Based on its unique hSSTR binding profile, (111)In-DOTA-lanreotide was suggested to be a potential radioligand for tumor diagnosis, and (90)Y-DOTA-lanreotide suitable for receptor-mediated radionuclide therapy. As opposed to (111)In-DTPA-DPhe(1)-octreotide and (111)In-DOTA-DPhe(1)-Tyr(3)-octreotide, discrepancies in the scintigraphic results were seen in about one third of (neuroendocrine) tumor patients concerning both the tumor uptake as well as detection of tumor lesions. On a molecular level, these discrepancies seem to be based on a "higherrdquuo; high-affinity binding of (111)In-DOTA-DPhe(1)-Tyr(3)-octreotide to hSSTR2 (K(d) 0.1-1 nM). Other somatostatin analogs with divergent affinity to the five known hSSTR subtype receptors have also found their way into the clinics, such as (99m)Tc-depreotide (NeoSpect(R); NeoTect(R)). Most of the imaging results are reported for neuroendocrine tumors (octreotide analogs) or nonsmall cell lung cancer ((99m)Tc-depreotide), indicating high diagnostic cabability of this type of receptor tracers. Consequently to their use as receptor imaging agents, hSSTR recognizing radioligands have also been implemented for experimental receptor-targeted radionuclide therapy. Beneficial results were reported for high-dose treatment with (111)In-DTPA-DPhe(1)-octreotide, based on the emission of Auger electrons. The Phase IIa study "MAURITIUS" (Multicenter Analysis of a Universal Receptor Imaging and Treatment Initiative, a eUropean Study) showed in progressive cancer patients (therapy entry criteria) with a calculated tumor dose > 10 Gy / GBq (90)Y-DOTA-lanreotide, the proof-of-principle for treating tumor patients with peptide receptor imaging agents. In the "MAURITIUS" study, cummulative treatment doses up to 200 mCi (90)Y-DOTA-lanreotide were given as short-term infusion. Overall treatment results in 70 patients indicated stable tumor disease in 35% of patients and regressive tumor disease in 10% of tumor patients with different tumor entities expressing hSSTR. No acute or chronic severe hematological toxicity, change in renal or liver function parameters due to (90)Y-DOTA-lanreotide treatment, were reported. (90)Y-DOTA-DPhe(1)-Tyr(3)-octreotide may show a higher tumor uptake in neuroendocrine tumor lesions and may therefore be superior for treatment in patients with neuroendocrine tumors. However, there is only limited excess to long-term and survival data at present. Potential indications for (90Y-DOTA-lanreotide are radioiodine-negative thyroid cancer, hepatocellular cancer and lung cancer. Besides newer approaches and recent developments of 188)Re-labeled radioligands, no clinical results on the treatment response are yet available. In conclusion, several radioligands have been implemented on the basis of peptide receptor recognition throughout the last decade. A plentitude of preclinical data and clinical studies confirm their potential use in diagnosis as well as "proof-of-principle" for therapy of cancer patients. However, an optimal radiopeptide formulatioents. However, an optimal radiopeptide formulation does not yet exist for receptor-targeted radionuclide therapy. Ongoing developments may result in peptides more suitable for this kind of receptor-targeted radionuclide therapy.
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PMID:Experience with indium-111 and yttrium-90-labeled somatostatin analogs. 1217 31

Globally, lung cancer has risen to the leading cause of cancer mortality in both sexes. Currently, the only potentially curable stage of the disease is the pulmonary nodule. Since numerous studies have documented that in any population of nodules only approximately fifty percent ultimately prove to be neoplastic, non-invasive evaluation of nodules to reduce surgical morbidity, mortality and cost is desirable. Recent nuclear medicine imaging modalities have shown promise in the accurate non-invasive characterization of pulmonary nodules. These new technologies exploit the biomolecular alterations of neoplastic cells. The somatostatin receptor is relatively over-expressed in pulmonary neoplastic tissue when compared to most benign tissue processes. A somatostatin analog-technetium ligand ((99m)Tc depreotide) has shown significant promise in the rapid, convenient, accurate and cost effective characterization of lung nodules with conventional gamma camera systems. The development of this agent required synthesis of a somatostatin receptor ligand of high affinity for the receptor subtypes operative in pulmonary neoplasia and the incorporation of technetium without loss of pharmacore specificity.
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PMID:Technetium labeled small peptide radiopharmaceuticals in the identification of lung cancer. 1217 34


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