Transiently transfected syn1-expressing HTR8 cells with and without stably expressed ERVH48-1 were then co-cultured with a heterotypic human endometrial adenocarcinoma cell line, Ishikawa cells, which endogenously express the syn1- and SUPYN-binding partner, SLC1A5, but do not endogenously express syn1 or SUPYN [15]. Here, ERVH48-1 is linked to endometrium adenocarcinoma.