Bile duct cancer (biliary tract cancer) is one of the most high-grade malignancies because of its invasiveness and metastasis. Study 1: we analyzed phenotypic changes and cell migration of the TFK-1 human extrahepatic bile duct cancer cells, co-cultured with MSC-43 human mesenchymal stem cells. When co-cultured with MSC-43 cells, the TFK-1 cells morphologically showed epithelial mesenchymal transition (EMT), and immunohistochemically decreased E-cadherin expression. Migration assay demonstrated that the TFK-1 cells co-cultured with MSC-43 cells showed significantly higher migration rate than the TFK-1 cells only (2.48 vs 1.82, p<0.001). Transwell migration assay revealed that theTFK-1 cells indirectly co-cultured with MSC-43 cells exhibited higher migration rate than the TFK-1 cells only (3.27 vs 1.67, p<0.005). The stromal mesenchymal cells are thought to play an important role of phenotypic changes and cell migration of human bile duct cancer. Study 2: we analyzed lymphatic invasion of the TFK-1 cells, using 3D human stromal tissues with lymphatic vessels. The TFK-1 cells showed epithelial mesenchymal transition (EMT) at the start of stromal invasion. Light microscopy and transmission electron microscopy demonstrated that TFK-1 cells became spindle in shape, i.e., EMT at the intravasation and extravasation. The 3D human stromal tissues with lymphatic vessels are thought to become a useful model analyzing the lymphatic invasion mechanisms of extrahepatic bile duct cancer.