Consistent with our findings in the HPA database, previous studies have also found that TOP2A (Panvichian et al., 2015; Ang et al., 2016; Xu et al., 2016; Li et al., 2018; Wang et al., 2018; Zhou et al., 2018), CCNB2 (Liu S. et al., 2018; Zhou et al., 2018), CDC20 (Li et al., 2014; Jin et al., 2015; Li L. et al., 2017; Yan et al., 2017; Fan et al., 2018), PRC1 (Chen et al., 2016; Wang Y. et al., 2017; Liu X. et al., 2018), and NUSAP1 (Zhang et al., 2013; Roy et al., 2018; Zhou et al., 2018) are overexpressed in HCC but are almost undetectable in non-tumorous livers. This evidence concerns the gene CCNB2 and hepatocellular carcinoma.