Existing studies have shown that FEN1 is highly expressed in various cancers, such as brain (Nikolova, Christmann & Kaina, 2009), lung (He et al., 2017; Zhang et al., 2018), breast (Abdel-Fatah et al., 2014), gastric (Wang, Xie & Chen, 2014), prostate (Lam et al., 2006) and pancreatic cancer (Isohookana et al., 2018), but its expression and role in HCC remains unclear. The gene discussed is FEN1; the disease is cancer.