Somatostatin receptors in normal and acromegalic somatotroph cells: the U-turn of the clinician to immunohistochemistry report - a review
Abstract
This is a narrative review of literature introducing somatostatin receptors (SSTRs) as part of understanding the somatotroph cells since they are positive in normal cells but also in tumoral cells as seen in somatotropinoma, a growth hormone (GH)-producing neoplasia, which causes acromegaly.
They are five subtypes of SSTRs (1 to 5), which are immunohistochemically positive in different proportions in somatotropinomas. SSTR types 2 and 5 are most frequent in GH-secreting adenomas and they are both targeted by medical therapy with somatostatin analogues (SSTAs) like first generation Octreotide and Lanreotide (mainly targeting SSTR2) and second generation Pasireotide (with highest affinity for SSTR5), thus heterogeneous SSTRs configuration into the tumor explains different pattern of response to treatment and it might predict it once the SSTRs immunostaining is performed.
Monoclonal antibodies are used for immunohistochemical detection of SSTRs; currently, a lack of standardization is presented, and scoring systems, such as Volante, H-score or human epidermal growth factor receptor 2 (HER2)-score, are applied. Immunoreactive markers like SSTRs are the U-turn in clinical practice regarding somatotropinomas since the configuration of subtypes 2 and 5 explains the responsiveness to medical therapy like SSTA.
Further achievement of disease control is imperiously necessary because acromegaly has an increased rate of morbidity and mortality.
NOTE: This publication cites (Ref. N.36): Giuseppe Di Bella, Biagio Colori, Roberta Scanferlato - The over-expression of GH/GHR in tumour tissues with respect to healthy ones confirms its oncogenic role and the consequent oncosuppressor role of its physiological inhibitor, somatostatin: a review of the literature. Neuro Endocrinol Lett. 2018 Sep;39(3):179-188.
See also:
- Official Web Site: The Di Bella Method;
- Somatostatin in oncology, the overlooked evidences - In vitro, review and in vivo publications;
- Publication, 2018 Jul: Over-Expression of GH/GHR in Breast Cancer and Oncosuppressor Role of Somatostatin as a Physiological Inhibitor (from Di Bella's Foundation);
- Publication, 2019 Aug: The Entrapment of Somatostatin in a Lipid Formulation: Retarded Release and Free Radical Reactivity (from Di Bella's Foundation);
- Publication, 2019 Sep: Effects of Somatostatin and Vitamin C on the Fatty Acid Profile of Breast Cancer Cell Membranes (from Di Bella's Foundation);
- Publication, 2019 Sep: Effects of somatostatin, curcumin, and quercetin on the fatty acid profile of breast cancer cell membranes (from Di Bella's Foundation);
- Publication, 2020 Sep: Two neuroendocrine G protein-coupled receptor molecules, somatostatin and melatonin: Physiology of signal transduction and therapeutic perspectives (from Di Bella's Foundation);
- The Di Bella Method (A Fixed Part - Bromocriptine and/or Cabergoline);
- The Di Bella Method (A Fixed Part - Calcium, 2 grams per day, orally);
- Neuroblastoma: Complete objective response to biological treatment;
- Oesophageal squamocellular carcinoma: a complete and objective response;
- Pancreatic Adenocarcinoma: clinical records on 17 patients treated with Di Bella's Method;