MUC4 and pancreatic ductal adenocarcinoma: Recently, three T-cell factor/lymphoid enhancer factor (TCF/LEF)-binding sites have been identified on the MUC4 promoter, and binding of fibrotic transcription factor β-catenin/TCF4 to the MUC4 promoter has been observed in cells from pancreatic ductal adenocarcinoma, inducing its expression [164] (Figure 9).