Alexander N, Marrano P, Thorner P, Naranjo A, Van Ryn C, Martinez D, Batra V, Zhang L, Irwin MS, Baruchel S. Prevalence and Clinical Correlations of Somatostatin Receptor-2 (SSTR2) Expression in Neuroblastoma. J Pediatr Hematol Oncol. 2019 Apr;41(3):222-227. doi: 10.1097/MPH.0000000000001326. PubMed PMID: 30334904; PubMed Central PMCID: PMC6600817.
Study ID Citation
Abstract
Alternative radiolabeled targeted agents are being investigated for children with relapsed neuroblastoma who do not respond to I131-metaiodobenzylguanidine (MIBG) therapy. DOTATATE targets somatostatin receptors (SSTR), particularly SSTR2, which are expressed on neuroblastoma cells. We investigated SSTR2 expression in neuroblastoma tumors (36 high risk; 33 non-high risk patients) and correlated SSTR2 levels with clinical features, norepinephrine transporter (NET) expression and MIBG avidity. SSTR2 and NET immunohistochemistry scores (0-3) were calculated on biopsies using digital image analysis based on staining intensity and distribution. Clinical data were correlated with SSTR2 expression. Median SSTR2 score for 69 patients was 1.31 (0.26-2.55). Non-high risk neuroblastoma was associated with higher SSTR2 score (p=0.032). SSTR2 expression did not correlate with age, INSS stage, MYCN amplification and histology. Higher SSTR2 scores were observed in MIBG-avid versus non-avid NB. SSTR2 score were not significantly associated with NET score (r=−0.062, p=0.62). Twenty-six patients who relapsed or progressed had a median SSTR2 score of 1.33 (0.26-2.55). Patients with neuroblastoma including relapsed or progressive disease showed SSTR2 expression at diagnosis, suggesting they could be candidates for radiolabeled DOTA-conjugated peptide imaging or therapy.