The presence of somatostatin receptors (SSTR1-5) in tumour cells indicates a potential for somatostatin to bind and suppress growth, as well as allowing for therapeutic treatment with somatostatin analogues.
The somatostatin receptor subtype 2 (sst2) behaves as a tumor suppressor when expressed and stimulated by its ligand somatostatin in pancreatic cancer.
5 days after tumor cell inoculation, followed by an i.p. injection of [(111)In]-DTPA-D-Phe1-octreotide 2 days later, showed a range of 15.3-60.4% median injected dose/gram (ID/g) in tumor at 4 h after injection compared with 3.5% ID/g when [125I]-Tyr1-somatostatin was administered and 0.3% ID/g when the negative control peptide [125I]-mIP-bombesin was administered.
Peptide receptor radionuclide therapy (PRRT) with Lu-DOTATATE is shown to be an effective therapeutic option for somatostatin-expressing neuroendocrine neoplasms.
Featuring a possible role of somatostatin analogs in combined endocrine therapies for breast cancer, our results seem to confirm that the sst2 status of the tumor should be previously investigated.
We set out to improve the effectiveness of somatostatin radiotherapy by preparing a chemical analog that would clear more slowly through the urinary tract and, concomitantly, have increased blood circulation half-life and higher targeted accumulation in the tumors.
Identification of somatostatin receptor subtypes and an implication for the efficacy of somatostatin analogue SMS 201-995 in treatment of human endocrine tumors.
The study shows that the different expression of SSTR2 and SSTR5 in GH-secreting adenomas is not significantly correlated with the secretory and proliferative phenotype, although the large, hypersecretory tumours and those with a poor sensitivity to somatostatin analogues seem to express low levels of SSTR2 mRNA.
All tumors were positive for panendocrine immunohistochemistry markers (chromogranin A and/or synaptophysin); 35% of NETs demonstrated focal positivity for pancreatic polypeptide, somatostatin, insulin, and/or glucagon; and no immunostaining for pancreatic and gastrointestinal hormones was observed in 65% of tumors.
Hyperthyroidism due to thyroid-stimulating hormone-secreting tumors accounts for 1% of tumors and is treated with surgery and somatostatin analogues if not surgically cured.
Non-symptomatic tumour versus symptomatic tumour (p = 0.002), and treatment with somatostatin analogues versus no treatment (p = 0.040) were associated with less diarrhoea.
Increased sstr expression results in increased binding of radiolabeled somatostatin analogs to the tumor cell, which enhances the efficacy of systemic radionuclide therapy.
NETs typically express somatostatin receptors on their cell surface, which can be targeted by 'cold' somatostatin analogs for therapy or by 'hot' radiolabeled somatostatin analogs for tumor localization and treatment.
Somatostatin analogue (SSTA) has been shown to inhibit the proliferation of some tumors through binding to somatostatin receptor (SSTR) and activation of Ras-, Rapl- and B-Raf-dependent extracellular signal-regulated kinase 2 (Erk2).
Similarly to what was observed in the major ampulla, 3 histotypes were found: (i) ampullary-type somatostatin-producing tumors (ASTs, 10 cases), characterized by somatostatin expression in most tumor cells, focal-to-extensive tubulo-acinar structures, often with psammoma bodies, MUC1 reactivity, and no or rare membranous reactivity for somatostatin receptor type 2A; (ii) gangliocytic paragangliomas (3 cases), characterized by the coexistence of 3 tumor cell types: epithelioid, often reactive for pancreatic polypeptide, ganglion-like cells, and S100 reactive sustentacular/stromal cells; and (iii) ordinary nonfunctioning NETs (3 cases), resembling those more commonly observed in the extra-ampullary duodenum.
In addition to the biochemical diagnostic, further radiologic and endoscopic imaging modalities are required moreover, somatostatin-receptor based functional imaging, using either Octreotide-scintigraphy or novel PET-based techniques with specific isotopes like Ga<sup>68</sup>-DOTA-octreotate, plays an important role for the detection of the primary tumor as well as for the evaluation of the tumor extent.
No association of these variants with PEG-V dose required for IGF-I normalization, adverse effects occurrence, and tumor regrowth was found in patients on PEG-V and on PEG-V + SST analog treatment.
Because somatostatin (SRIF) receptors (ssts) are present in colorectal carcinomas, the treatment with targeted cytotoxic SRIF analogue AN-238, consisting of 2-pyrrolinodoxorubicin (AN-201) linked to octapeptide SRIF carrier RC-121, may overcome this resistance by producing a higher concentration of the cytotoxic agent in the tumors.
Here, we report a patient with an highly aggressive, dopamine-resistant prolactinoma, who only achieved biochemical and tumor control during pasireotide long-acting release (PAS-LAR) therapy , a second-generation somatostatin receptor ligand (SRL).
Tumor localization in non-Hodgkin lymphomas and Hodgkin's disease can be visualized by in vivo somatostatin receptor scintigraphy, contributing to establish the diagnosis and the stage of the disease.Recently. somatostatin receptors have been in vivo and in vitro detected in human thymic tumors.