CO-IP (co-immunoprecipitation) assay showed that DDR1 was coimmunoprecipitated with STAT3, and STAT3 was coimmunoprecipitated with DDR1 in HCC cells (Figure 4C), and there was a higher binding content in HCC tissues between DDR1 and STAT3 than that in adjacent tissues (Figure 4D). Here, STAT3 is linked to hepatocellular carcinoma.