PNPLA3 and hepatocellular carcinoma: Metabolism-related single nucleotide polymorphisms (such as PNPLA3, TM6SF2, and HSD17B13) increase susceptibility to HCC in non-cirrhotic individuals, while environmental carcinogens, including aflatoxin B1 and aristolochic acid, can directly induce somatic mutations and synergize with HBV infection to promote tumorigenesis.