Objective: To clarify the clinicopathologic significance of the expression of the Bcl-2 protein (pBcl-2) and the Bax protein (pBax), and their clinical implications in Chinese and Japanese patients with human invasive ductal carcinomas (IDCs) of the pancreas.
Methods: The study included 59 Chinese and 65 Japanese patients with IDCs of the pancreas. pBcl-2 and pBax expression were immuno-stained with streptavidin-biotin (SAB) method.
Results: pBcl-2 (+) was seen in 35.6% of Chinese and in 23.1% of Japanese patients. pBax (+) was seen in 49.2% of Chinese and 64.7% of Japanese patients. A comparison between them showed that there were significant differences in the male patients, in the patients with the moderately differentiated cancer, and in the elderly patients (chi squared = 4.447, P = 0.035; chi squared = 4.114, P = 0.043; chi squared = 6.657, P = 0.010 respective). In both Chinese and Japanese patients, those with pBcl-2 positive expression had a significantly higher survival rate than those with negative one (chi squared = 9.99, P = 0.0016; chi squared = 7.63, P = 0.0058). The group with pBax positive expression had a significantly higher survival rate in Japanese patients (chi squared = 9.37, P = 0.0022). Japanese patients whose tumors exhibited pBcl-2 and pBax positive immunostaining survived significantly longer than Chinese patients did (chi squared = 4.48, P = 0.0342; chi squared = 5.23, P = 0.023).
Conclusions: The expressions of both pBcl-2 and pBax are high found in Chinese and Japanese patients. The pBcl-2 positive expression implies a better prognosis in both Chinese and Japanese patients with IDCs of the pancreas. The effect of pBax expression on prognosis is different between Chinese and Japanese patients.