Serum PIVKA-II and AFP levels and the serum γ-GT/ALT ratio were positively correlated with tumour size in patients with HCC (r = 0.520, P < 0.001; r = 0.328, P < 0.001; r = 0.209, P = 0.001, respectively; Fig. 1A–C). The gene discussed is GPT; the disease is hepatocellular carcinoma.