ERVW-1 and hepatocellular carcinoma: Data of immunohistochemistry (IHC) also showed that 84 out of 103 (81.55%) HCC specimens were positively stained, whereas only 13 out of 53 (24.53%) adjacent tissues were positive for Syncytin-1 (p < 0.001; Fig. 1d, Supplementary Table S3).