DDX19B and hepatocellular carcinoma: In training test, the stepwise multivariate Cox regression was applied and a total of 4 SFs (DNAJC6, ZC3H13, IGF2BP3, and DDX19B) were selected to construct the final prognostic risk score model The normalized expression of these 4 SFs and their corresponding coefficients, displayed in Table 3, were used to calculate risk scores for HCC patients with the following risk score calculation formula: risk score = (0.28336 × DNAJC6 expression) + (− 0.4438 × ZC3H13 expression) + (0.226331 × IGF2BP3 expression) + (− 0.63347 × DDX19B expression).