ERVW-1 and hepatocellular carcinoma: The relative expression levels of syncytin-1 in serum exosomes of HCC patients showed statistically significant differences in relation to lymph node metastasis, degree of differentiation, CNLC staging, and whether they were infected with hepatitis B virus (P < 0.05), but not with age, gender, or history of alcohol consumption (P > 0.05) (Table 1).