The tumour suppressor gene product p53 is believed to play an important role in the progression of human malignant tumours through mutation and over-expression. Using a microwave oven heating method, we have detected over-expression of p53 in buffered-formalin fixed, paraffin-embedded sections of oesophageal carcinomas immunohistochemically and examined the relationship between the p53 over-expression and postoperative survival. Employing a monoclonal antibody (pAb1801), nuclear p53 was detected in 56 of 105 (53%) tumour specimens. Homogeneous, heterogeneous, and focal immunostaining patterns were noted. No immunostaining was found in adjacent benign tissues. The results in buffered-formalin fixed sections were similar to those in the frozen sections. The cumulative survival rate of patients with p53 expression was significantly lower than that of the patients without expression (P < 0.05), even though there were no significant differences between the clinicopathological features of the two groups. The results indicate that the nuclear accumulation of p53 might be an independent prognostic factor in patients with oesophageal squamous cell carcinomas.