Somatostatin receptor 2A protein expression characterizes anaplastic oligodendrogliomas with favorable outcome

Abstract

Diffuse gliomas are classified according to the 2016 WHO Classification of Tumors of the Central Nervous System, which now defines entities by both histology and molecular features.

Somatostatin receptor subtype 2A (SSTR2A) expression has been reported in various solid tumors as associated with favorable outcomes. Its expression has been reported in gliomas with uncertain results regarding its prognostic value.

The objective of this study was to assess the prognostic impact of SSTR2A protein expression in a large cohort of grade III and IV gliomas classified according to the updated 2016 WHO classification. We further validated our result with an independent cohort of low grade glioma using dataset generated by The Cancer Genome Atlas (TCGA) Research Network.

We analyzed clinical and molecular data from 575 patients. SSTR2A protein expression was evaluated using immunohistochemistry on tissue microarrays. High expression of SSTR2A protein associated with the anaplastic oligodendroglioma IDH-mutant and 1p/19q-codeleted subgroup (p < 0.001). Among these tumors, SSTR2A protein expression was significantly associated with a lower proliferative index, the absence of microvascular proliferation and the absence of necrosis (p < 0.001).

Furthermore SSTR2A protein expression associated with better overall survival (p = 0.007) and progression-free survival (p = 0.01) in both univariate and multivariate analysis when adjusted by the age, the presence of necrosis and the mitotic index.

Similar results were obtained regarding SSTR2 mRNA expression in the TCGA low grade glioma, subtype IDH-mutant and 1p/19q-codeleted, dataset.SSTR2A might represent an attractive biomarker and therapeutic target in anaplastic oligodendroglioma IDH-mutant and 1p/19q-codeleted specific subgroup.

Understanding the implicated molecular pathways may represent a step forward to improve therapeutic approaches.

 

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See also:

- Official Web Site: The Di Bella Method;

- Somatostatin in oncology, the overlooked evidences - In vitro, review and in vivo publications;

- The Di Bella Method (A Fixed Part - Somatostatin, Octreotide, Sandostatin LAR, analogues and/or derivatives);

- The Di Bella Method (A Fixed Part - Cyclophosphamide and/or Hydroxyurea tablets, one or two per day);

- Recurrent Glioblastoma Multiforme (grade IV – WHO 2007): a case of complete objective response achieved by means of the concomitant administration of Somatostatin and Octreotide – Retinoids – Vitamin E – Vitamin D3 – Vitamin C – Melatonin – D2 R agonists (Di Bella Method – DBM) associated with Temozolomide;

- The Di Bella Method DBM improved survival objective response and performance status in a retrospective observational clinical study on 23 tumours of the head and neck;

- 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;

- The Di Bella Method Increases by the 30% the survival rate for Pancreas tumors and for this reason should be proposed as first line therapy for this type of cancer;

- The Di Bella Method (DBM) in the treatment of prostate cancer: a preliminary retrospective study of 16 patients and a review of the literature.