ERVFRD-1 and carcinoma: Although Syncytin-2 and Syncytin-3 like Syncytin-1 were proven to be cell fusogenic using ex-vivo assays, and Syncytin-2 associated with immunosuppressive capabilities, no report to date is known about Syncytin-2 and Syncytin-3 expression in primary carcinomas [28, 57].