ERV3-1 and neoplasm: Furthermore, in the cohorts analyzed in this study, HEMO's activation in solid tumors made this retroviral envelope gene stand out from others such as syncytin‐1 (ERVW‐1) and ERVV‐2 for which we mainly found low expression, from syncytin‐2 (ERVFRD‐1) usually inactivated in tumor samples, and from ERV3‐1 which mainly shows non‐tumor‐specific activation.