SMAD3 and hepatocellular carcinoma: To gain further insight, the authors investigated the clinical relevance of LINC00261 in HCC and performed immunohistochemistry (IHC) on patient samples to correlate LINC00261 expression and found that low levels of LINC00261 were associated with high levels of p-SMAD3 (phospho-small mothers against decapentaplegic homolog 3), a molecule activated during TGF-β1 signaling, which promotes EMT (epithelial-mesenchymal transition), stemness, and metastasis (Figure 3).