Whereas a supportive role for spermatogenesis might be postulated for Bcl-2 expressing peritubular cells in dogs in the case of CAO, there is no doubt that the significant immune cell infiltration is rather detrimental for spermatogenesis, causing disruption of spermatogenesis (late/early arrest), germ cell depletion up to Sertoli cell-only syndrome, fibrosis, etc., as clearly visible in CAO [5]. Here, BCL2 is linked to Sertoli Cell-Only Syndrome.