In a recently published work, Yu and colleagues demonstrated that syncytin-1 3’-LTR mutations (142T>C and 277A>G) were significantly associated with syncytin-1 overexpression in urothelial cell carcinomas [92] suggesting that mutations could result in the up-regulation of cell fusion associated molecules concomitant with an increased cell fusion frequency. This evidence concerns the gene ERVW-1 and transitional cell carcinoma.