Endocrine Abstracts

Introduction
The prognosis in head and neck cancer has remained unchanged over the last 20 years (overall 5 year survival 50-60 percent), and is adversely affected by tumour angiogenesis. The effects of the anti-proliferative and anti-angiogenic peptide somatostatin (SST) are mediated through a family 5 receptors (SSTRs 1-5), whilst the angiogenic cytokine vascular endothelial growth factor (VEGF) acts predominantly via 2 receptors: FLK and FLT. The objective of this study was to determine the level of expression of SSTRs 1-5, VEGF, FLK and FLT in both benign and malignant laryngeal pathology.
Methods
Archival samples of 6 Reinke's oedema (non-malignant) and 12 laryngeal squamous cell carcinoma sections were analysed by immunohistochemistry for expression of SSTRs 1-5, VEGF, FLK and FLT, using the peroxidase-streptavidin-biotin complex method. The proportion of epithelial cells showing positive staining was assessed independently by 2 observers.
Results
A high level of SSTR 1 and 5 expression (greater than 50 percent of epithelial cells) was observed in 50 percent of the tumours, compared to only 17 percent and 33 percent of benign samples. A high level of expression of SSTR2 was observed in 60 percent of malignant and 50 percent of benign cases, with virtually no expression of SSTRs 3 and 4 in either group. A high level of VEGF expression was observed in 40 percent of tumours, but none of the benign samples. High levels of FLK and FLT were expressed in 70 percent and 50 percent of tumours respectively, compared to only 17 percent of benign samples.
Conclusion
Relative overexpression of SSTRs 1 and 5, VEGF, FLK and FLT was seen in malignant laryngeal epithelium compared to benign laryngeal epithelium; therefore, the anti-angiogenic effect of SST analogues and VEGF inhibitors, may have a potential therapeutic role in carcinoma of the larynx.