Histological phenotype is correlated with the wall-invasion pattern of gallbladder adenocarcinoma.

Gallbladder carcinoma (GBC) is one of the most aggressive malignancies, and frequently shows vascular invasion and lymph node metastasis. Our previous study has classified the wall-invasion pattern of GBC into two groups, i.e., infiltrative growth type (IG type) and destructive growth type (DG type). The DG type was significantly associated with poor clinical outcome. In this study, we analyzed the relationship between the wall-invasion pattern and the histological phenotype of GBC, using 61 surgically-resected primary gallbladder adenocarcinomas. Histologically, the 61 cases were classified into the biliary (44 cases, 72.1%), gastric foveolar (13 cases, 21.3%), and intestinal (4 cases, 6.6%) types. Biliary type frequently exhibited MUC1, but less frequently showed MUC2, MUC5AC, and MUC6. The biliary type and MUC1 expression were significantly correlated with DG type wall-invasion pattern (P = 0.020 and P < 0.001, respectively). In conclusion, histological phenotype and mucin expression were thought to be indicators of aggressiveness of GBC.