MSTN and hepatocellular carcinoma: The predictive performance of serum myostatin levels for the development of HCC was higher in patients with age < 65 years old than that in patients with age ≥ 65 years old: Time-dependent AUROC of serum myostatin levels for development of HCC within 5 years was 0.81 (95% confidence interval [CI] 0.77–0.83) in those with age < 65 years old (n = 874) and 0.68 (95% CI 0.61–0.74) in patients with age ≥ 65 years old (n = 203).