Apoptosis and cell surface GRP78 expression in benign and malignant parotid gland tumors

Introduction: Glucose-regulated protein 78 (GRP78) has emerged as an important regulator of tumour cell signalling and viability. We have analysed cell surface GRP78 in benign and malignant parotid salivary tumours in correlation to apoptosis.

Materials and methods: Primary cell-cultures were produced from tissue biopsies. Cell surface GRP78 stained by anti GRP78 antibody was analysed by fluorocytometry. Apoptosis was determined by Annexin V/PI.

Results: A significant decrease in the percentage of cell surface GRP78 was determined in the benign parotid tumour in comparison to normal tissue. Cell surface GRP78 expression in malignant tumours was significantly higher and correlated with decrease in apoptosis.

Conclusion: This study is the first report describing cell surface GRP78 expression in parotid salivary tumour. The evidence of high surface GRP78 expression in malignant parotid tissue in contrast to the benign tumour might add a diagnostic tool and serve as a future target for treatment of malignant parotid tumours.