AFP and neoplasm: Among the matched pairs, it was evident that the PVTT group had more aggressive tumor characteristics in terms of tumor size (7.1 ± 3.6 vs. 3.6 ± 2.4), serum AFP level (12,514.5 ± 36,419.6 vs. 1025.6 ± 4349.6), multiple HCCs (44.7% vs. 33.7%), and extrahepatic metastasis (18.0% vs. 3.6%; all Ps < 0.05) (Supplementary Table 2).