MUC4 and pancreatic neoplasm: In our previous studies [14, 16], we first proved that its splice variant, MUC4/Y (NCBI Reference Sequence: NM_004532.5) can be as a model of MUC4 (MUC4 gene fragment is more than 30KB, too huge to clone and eukaryotic express) in pancreatic cancer for function and mechanism research, as shown in Additional File 4 (Supplementary Figure S1).