Based on real-time PCR analysis, the HCC cell line SMMC-7721 cells constitutively expressed a high level of TLR4, whereas Hep3B cells had low levels; on the other hand, the expression of TLR4 was almost absent in HepG2 and Huh7 cells (Figure 3A). The gene discussed is TLR4; the disease is hepatocellular carcinoma.