VRK1 and hepatocellular carcinoma: The subgroup analysis further revealed that only VRK2 expression was closely associated with TNM stage in the three HCC cohorts, whereas VRK1 expression was associated with TNM stage in the TCGA and ICGC cohorts and VRK3 expression was associated with TNM stage in the ICGC and GSE14520 cohorts (Figure 2B).