SMAD3 and neoplasm: Our previous study found that MUC1 gene silencing decreased Smad3 mRNA level in HCC cells [17], and another study has shown that MUC1 can active JNK to inhibit cell apoptosis [32], thus leading to the hypothesis that MUC1 shifts Smad3 from tumor-suppression to oncogenesis by activating JNK in HCC cells.