The ability of JSRV Env to transform cells in culture, the identification of Hyal2 as the cell-surface receptor for the Env protein of JSRV, and the localization of Hyal2 to the chromosome 3p21.3 lung cancer tumor suppressor locus suggested the hypothesis that JSRV might cause cancer by inhibiting a tumor suppressor activity of Hyal2 [3]. This evidence concerns the gene ERVW-1 and cancer.