Validation of FEN1's diagnostic value in other three HCC cohorts showed that the AUC levels were 0.963 (P < 0.001), 0.976 (P < 0.001), and 0.951 (P < 0.001) in GSE14520 (Figure 5(b)), GSE36376 (Figure 5(c)), and GSE45436 (Figure 5(d)) databases, respectively. This evidence concerns the gene FEN1 and hepatocellular carcinoma.