Furthermore, COL12A1 mRNA and protein expression was similar between clinical HCC tissue and nontumor liver tissue samples (Fig. 2B, Additional file 1: Fig. S1B), whereas COL12A1 protein was downregulated in human HCC cell lines relative to normal liver cell line HL7702 (Fig. S1C). Here, COL12A1 is linked to hepatocellular carcinoma.