Histological assessment of the testes from the beagle cohort at the completion of the original study showed that none of the dogs had signs of tumours or larger lesions [28,30], except for one (excluded from the present investigation), even though treatment with the slow-release GnRH-agonist implant induced an arrest of spermatogenesis at the level of spermatogonia/spermatocytes [29]. The gene discussed is GNRH1; the disease is neoplasm.