Expression levels of HMGA2 and CD9 and its clinicopathological significances in the benign and malignant lesions of the gallbladder

Background: The objective of this study was to investigate CD9 and HMGA2 expression and its clinicopathological significance in benign and malignant lesion tissues of the gallbladder. Methods: The resected specimens of 108 cases of gallbladder adenocarcinoma, 46 cases of adjacent tissue, 15 cases of polyps and 35 cases of chronic cholecystitis were made into conventional paraffin- embedded sections, using the method of EnVision immunohistochemistry to stain HMGA2 and CD9. Results: HMGA2 expression of gallbladder adenocarcinoma was significantly higher than that of adenocarcinoma adjacent tissues (= 16.13, P < 0.01), polyps (= 8.19, P < 0.01) and chronic cholecystitis (= 21.41, P < 0.01); but CD9 expression was the opposite (P < 0.05 or P < 0.01). The positive rate of HMGA2 expression from the cases that had well-differentiated adenocarcinoma, with the largest tumor diameter < 2 cm, and without lymph node metastasis, and that did not invade the surrounding tissue was significantly lower than that of HMGA2 expression from the cases that had poorly differentiated adenocarcinoma, with the largest tumor diameter >= 2 cm, lymph node metastasis, and that invaded the surrounding tissues (P < 0.05 or P <= 0.01). The positive rate of CD9 expression from the cases that had well-differentiated adenocarcinoma, with the largest tumor diameter < 2 cm, and without lymph node metastasis, and that did not invade the surrounding tissue was significantly higher than that of CD9 expression from the cases that had poorly differentiated adenocarcinoma, with the largest tumor diameter >= 2 cm, lymph node metastasis, and which invaded the surrounding tissues (P < 0.05 or P < 0.01). The Kaplan-Meier survival analysis showed that after surgery, the survival period of HMGA2 expression-positive cases was significantly lower than that of HMGA2 expression-negative cases (P = 0.020), but the survival period of CD9 expression-positive cases was significantly higher than that of cases with CD9 expression-negative (P = 0.019). Cox multivariate regression analysis showed that the HMGA2 positive expression and/or CD9 negative expression was an important indicator reflecting the poor prognosis of gallbladder cancer. Conclusion: The expression of HMGA2 and/or CD9 might be closely related to the carcinogenesis, clinical biological behaviors and prognosis of gallbladder adenocarcinoma.