BSG and hepatocellular carcinoma: To validate the robustness of TM4SF4 as an optimal therapeutic target in HCC, the expression of TM4SF4 in normal human tissues and HCC cases were compared with those of seven other cell surface proteins commonly being researched for HCC therapeutic development, i.e., CD24, CD133 (PROM1), CD147 (BSG), EPCAM, GPC3, MET, and MUC1.