ets-1 expression in extrahepatic bile duct carcinoma and cholangiocellular carcinoma

ets-1 is a transcription factor known to induce the expression of various genes important for carcinoma progression. However, its clinical significance does not seem to be uniform for all carcinomas. In this study, we investigated the ets-1 expression in 41 extrahepatic bile duct carcinomas (BDC) and 19 cholangiocellular carcinomas (CCC). Epithelial cells of normal ducts only occasionally expressed ets-1, whereas cells of reactive ducts and dysplastic ducts were often positive for this protein. On the other hand, 61.0% of BDC and 21.6% of CCC were classified as ets-1-positive, because more than 5% of the carcinoma cells expressed ets-1. The expression of ets-1 showed inverse relationships with the Ki-67-labeling index and vascular and perineural invasion of BDC, whereas no such relationships could be established in CCC. Furthermore, the well-differentiated BCD more frequently expressed ets-1. These results suggest that ets-1 works as a transcription factor in malignant transformation and progression in early phases of BDC.