Evaluation of somatostatin, CXCR4 chemokine and endothelin A receptor expression in a large set of paragangliomas

Abstract

Paragangliomas are predominantly benign tumors, but in some cases invasive growth and also metastasis are observed. Given the limited number of nonsurgical treatment options, novel target structures for diagnostics and therapy of this tumor entity are urgently needed.In the present study, expression of all five somatostatin receptor (SST) subtypes, chemokine receptor CXCR4 and endothelin receptor type A (ETA) was assessed by means of immunohistochemistry in a total of 66 paraffin-embedded paraganglioma samples from 55 patients. The stainings were rated by means of the Immunoreactive Score and correlated to clinical data and to succinate dehydrogenase subunit B (SDHB) expression.SST2A was by far the most prominent receptor in the paragangliomas investigated. It was present in 89% of the tumors at a high intensity, followed by SST5, SST3, SST1 and SST4, which were detected in 47%, 35%, 35% and 13% of the samples, respectively. SDHB positive tumors exhibited significantly higher SST2A and SST3 expression as compared to SDHB negative cases. There was no correlation between SST and Ki-67 expression or grading of the tumors and no difference in SST expression between primary tumors and metastases. Cell surface expression of CXCR4 and ETA was detected only in few samples. On tumor capillaries, however, exceptionally strong staining for these two receptors was noticed in the vast majority of the tumors.In conclusion, paragangliomas are well suited for SST2A-based diagnostics and treatment modalities. An indirect targeting of these highly vascularized tumors via CXCR4 or ETA may also represent a promising future strategy.

Immunohistochemical identification of complement peptide C5a receptor 1 (C5aR1) in non-neoplastic and neoplastic human tissues

“…From the paraffin blocks, 4-μm sections were prepared and floated onto positively charged slides. Immunostaining was performed by an indirect peroxidase-labelling method as previously described [ 13 ]. Briefly, sections were dewaxed, microwaved in 10 mM citric acid (pH 6.0) for 16 min at 600 W, and incubated with {5227} (dilution: 1:500) overnight at 4°C.…”

Comprehensive Assessment of GPR68 Expression in Normal and Neoplastic Human Tissues Using a Novel Rabbit Monoclonal Antibody

“…From the paraffin blocks, 4-µm sections were prepared and floated onto positively-charged slides. Immunostaining was performed by an indirect peroxidase labelling method as described previously [38]. Briefly, sections were dewaxed, microwaved in 10 mM citric acid (pH 6.0) for 16 min at 600 W, and incubated with 16H23L16 (dilution: 1:500) overnight at 4 °C.…”

Comprehensive assessment of tissue and serum parameters of bone metabolism in a series of orthopaedic patients

“…Sections of each sample were stained with hematoxylin and eosin (HE) according to standard laboratory protocols or by immunohistochemistry. Immunostaining was performed using an indirect peroxidase labelling method, as described previously [8]. Briefly, sections were dewaxed, microwaved in 10 mM citric acid (pH 6.0) for 16 min at 600 W, and then incubated overnight at 4°C with a polyclonal rabbit anti-human PTH1R antibody (antibody 1781; 0.1 μg/mL; Gramsch Laboratories, Schwabhausen, Germany), which was developed and extensively characterized by our group recently [9], a monoclonal mouse-anti-human OPG antibody (clone 5G2, Acris Antibodies, Herford, Germany; dilution, 1:100), or a mouse monoclonal anti-human RANKL antibody (clone 12A668; Enzo Life Sciences, Farmingdale, NY, USA; dilution, 1:750).…”