CD9 and adenocarcinoma: The positive rates of HMGA2 were significantly lower in the cases of well-differentiated adenocarcinoma with a maximal diameter of mass <2 cm, no-metastasis of lymph node, and no-invasiveness of regional tissues than those of poorly-differentiated adenocarcinoma, maximal diameter of mass >2 cm, metastasis of lymph nodes, and invasiveness of regional tissues in gallbladder adenocarcinoma (P <0.05 or P <0.01), but the CD9 expression was the opposite (P <0.05 or P <0.01).