TAP1 and hepatocellular carcinoma: Furthermore, ChIP assay validated that after immune precipitation with antibodies against GLI1 or GLI2, the potential GLI‐binding sequence within the TAP1 promoter could be amplified and visualized in gel of PCR products from the precipitated DNA, and it appears to be that the GLI1/2 transcription factors elicit TAP1 transcription when they bind to the putative sequence in poorly differentiated hepatoma cells (Figure 7C).