Serum DKK1 levels were significantly higher in patients with HCC (n = 9; mean 399.78 ± 113.81 pg/mL) than in the healthy controls (n = 4; mean 253.37 ± 63.08 pg/mL) and patients with liver diseases except HCC (mean 183.35 ± 175.92 pg/mL) (hepatitis B virus [n = 7], hepatitis C virus [n = 3], liver cirrhosis [n = 6], and fatty liver [n = 4]) (all P < 0.05) (Fig. 1B). Here, DKK1 is linked to hepatocellular carcinoma.