Ki-67 and c-jun expression in pancreatic cancer: a prognostic marker?

The proto-oncogene c-jun is involved in cell proliferation and Ki-67 antigen permits determination of the proportion of proliferating tumour cells. The expression of c-jun and Ki-67 in pancreatic cancer and their relation with tumour histological features and patients survival were evaluated. Specimens were obtained as follows: 14 pancreatic cancer from patients radically operated, 8 liver metastases from subjects submitted to palliation, 5 normal pancreas from organs donors and 5 chronic pancreatitis. Ki-67 and c-jun were studied by immunohistochemistry. The percentage of tumour cells stained for c-jun was increased in 11/14 cases. A high c-jun expression was more frequently found in liver metastases than in pancreatic cancer tissue (p=0.031). The frequency of high c-jun expression was more elevated in short-term as compared to long-term survivors (Fisher's exact test, p=0.031 and log-rank, p=0.03). The percentage of tumour positive cells for Ki-67 showed a mean value of 12.8% in primary pancreatic cancer and was lower than in the liver metastases (32.5%) (p=0.029). Significantly lower values were found in long-term (6.5%) as compared to the short-term survivors (18.1%) (p=0.032 and log-rank, p=0.006). A positive relation was demonstrated with stage (p<0.05), lymph node state (p=0.045) and perineural invasion (p=0.0001). In the multivariate analysis the Ki-67 staining was the most important determinant of long-term survival (p=0.005). c-jun and Ki-67 are overexpressed in pancreatic carcinoma, but only Ki-67 is a strong predictive factor.