Serum fibroblast growth factor-19 as a diagnostic biomarker of hepatocellular carcinoma and indicator of portal vein thrombosis: a cross-sectional study

Abstract Background Hepatocellular carcinoma (HCC) remains a major cause of cancer-related mortality worldwide. The limitations of alpha-fetoprotein (AFP) as a diagnostic biomarker have prompted the search for novel markers. Fibroblast growth factor-19 (FGF19) is involved in hepatocarcinogenesis and may also reflect tumor aggressiveness. Portal vein thrombosis (PVT) is a clinically important complication of HCC that is associated with advanced disease, limited therapeutic options, and poor prognosis. This study aimed to evaluate the diagnostic performance of serum FGF19 in HCC and to investigate its association with aggressive tumor features, particularly PVT. Methods This comparative cross-sectional study was conducted between March 2023 and June 2024 and included 90 patients: 60 patients with newly diagnosed, treatment-naïve HCC and 30 patients with liver cirrhosis. Serum FGF19 and AFP levels were measured. Diagnostic performance was assessed using receiver operating characteristic (ROC) curve analysis. Factors associated with PVT were evaluated using univariate and multivariate logistic regression analyses. Results Serum FGF19 levels were significantly higher in the HCC group than in the cirrhosis group (median 133.4 pg/mL vs. 63.0 pg/mL, p < 0.001). FGF19 distinguished HCC from cirrhosis with excellent accuracy (AUC = 0.964; 95% CI: 0.928-1.000), comparable to AFP (AUC = 0.934; 95% CI: 0.885–0.983; DeLong test, p = 0.185). At a cut-off value > 71.4 pg/mL, FGF19 showed 93.3% sensitivity and 90.0% specificity. Among patients with HCC, FGF19 levels were significantly higher in those with PVT than in those without PVT ( p < 0.001). FGF19 > 130 pg/mL was independently associated with PVT (adjusted OR = 11.03; 95% CI: 1.89–64.22; p = 0.008). ROC analysis for prediction of PVT showed an AUC of 0.848 (95% CI: 0.734–0.962); at a cut-off > 130.1 pg/mL, sensitivity was 90.0%, and specificity was 83.3%. Conclusions Serum FGF19 demonstrated high accuracy for differentiating HCC from cirrhosis and was independently associated with PVT. These findings suggest that FGF19 may serve as both a diagnostic biomarker and an indicator of aggressive tumor biology in HCC.