AFP and neoplasm: Subgroup analysis of the four-gene signature in the complete cohort was performed, and significant correlations between RS and OS were maintained in Asians (p < 0.001, Supplementary Figure S6A and S6B) and in patients whose serum AFP ≥ 20 ng/ml (p = 0.079, Supplementary Figures S6C and S6D), whereas RS value was associated with OS for the two subgroups of TNM stage and tumor grade (Supplementary Figures S6E-H).