Notably, both FEN1 expression (RNA level: log2FC = 0.32, P < 0.0001, Nanjing cohort; protein-level: log2FC = 0.45, P < 0.0001, Nanjing cohort) and DNA replication activity (RNA level: log2FC = 0.39, P = 1.40 × 10−19, Nanjing cohort; protein-level: log2FC = 0.34, P = 6.43 × 10−5, Nanjing cohort) were significantly increased in colorectal tumors and were positively associated with one another at both the RNA (r = 0.85, P < 2.20 × 10−16, Nanjing cohort) and protein (r = 0.72, P = 2.50 × 10−8, Nanjing cohort) levels (Fig. 3C and Supplementary Fig. 3 [available online]). This evidence concerns the gene FEN1 and colorectal neoplasm.