SMAD3 and neoplasm: Tumor SMAD3 correlated with poor PDAC outcomes such as tumor size and metastasis in PDAC patients.[13] Activin A signals through canonical SMAD3‐dependent pathways and/or non‐canonical pathways which involves p38 phosphorylation.[8] To understand the potential signaling pathway of activin A in PDAC, we analyzed the phosphorylation status of tumor SMAD3 and p38 proteins (Figure 4H).