Lack of vascular invasion, low serum alpha-fetoprotein (AFP) level, histologic grade G1/G2, and tumor-node-metastasis (TNM) stage I/II were associated with the C1 or C3 clusters; presence of vascular invasion, advanced TNM stage (III/IV), histologic grade (G3/G4), and high serum AFP level were associated with the C2 cluster (Supplementary Table 6). Here, AFP is linked to neoplasm.