TGFB1 and hepatocellular carcinoma: Multiple mechanisms underlying impaired sensitivity to sorafenib in HCC have been investigated, including Wnt/β-catenin, TGFβ, Ras/MEK/ERK, PI3K/Akt, TNFα/NF-κB, and JAK/STAT pathways, autophagy, epithelial-mesenchymal transition, cancer stem cells, tumor microenvironment, and epigenetic regulation (involving miR-222, miR-494, miR-21 and miR122) [3].