Objective:To investigate the expression of PUMA (p53 up-regulated modulator of apoptosis) and ABCG2 (ATP-binding cassette subfamily G member 2) in adenocarcinoma of common bile duct (CBD) and adjacent non-cancerous tissue  and their clinicopathological correlations.
Methods:The surgical specimens of 40 cases of CBD adenocarcinoma and paired adjacent CBD tissue in 15 of these  cases were paraffin embedded and sectioned using conventional method. The expression level of PUMA and ABCG2 was detected with immunohistochemical staining.
Results:The positive expression rate and scores of PUMA and ABCG2 in adenocarcinoma were significantly higher than those in adjacent tissues (PUMA: 67.5% vs.13.3%, P=0.001， 2.58±1.84  vs. 0.53±1.13, P=0.000; ABCG2: 60.0%  vs. 13.3%, P=0.002，2.28±1.88  vs. 0.53±1.13, P=0.001). The adjacent CBD tissues that showed positive expression of PUMA and ABCG2 totally presented with atypical hyperplasia of slight to moderate degree. The positive expression rates of PUMA and ABCG2 in the cases of histologic grade I and lymph node without metastasis were significantly lower than those of histologic grade II or III with involved lymph node (P＜0.05 or P＜0.01). There was a closely positive correlation between the expression scores of PUMA and ABCG2 in CBD adenocarcinoma (r=0.65, P=0.000).
Conclusions:The expression of PUMA and ABCG2 is closely correlated with the carcinogenesis and clinical biological behaviors of CBD adenocarcinoma, and the high-level expression of both proteins predicts a poor prognosis.