Protease-activated receptor-2 (PAR-2) is essential for the initiation and development of tumours, suggesting that the detection of PAR-2 expression might serve as a clinical marker in the prediction or diagnosis of clinical outcomes of malignant neoplasia. Using immunohisto chemical methods, this study investigated whether the detection of PAR-2 protein had clinical implications for patients with oesophageal squamous cell carcinoma (OSCC). PAR-2 protein was present at a high level in primary OSCC sites but at a low level in normal oesophageal tissue. The level of PAR-2 protein in tumours was significantly correlated with the clinical stage and histological grade of disease. Patients with tumours highly positive for PAR-2 protein had a significantly worse prognosis than those with lower PAR-2 levels. Thus, the over-expression of PAR-2 is a characteristic feature of OSCC and suggests that the immuno histochemical detection of raised levels of PAR-2 may be a potentially useful prognostic indicator.