title: Polycystic kidney and renal cell carcinoma in Japanese and Chinese toad hybrids.
abstract: Frequent development of renal cell carcinomas in hybrids between Japanese toads (Bufo japonicus) and imported Chinese toads (Bufo raddei) was first reported by 2 of our authors in 1987. Such renal tumors of toads had never been observed previously in the laboratory. To confirm the observation and to establish a new animal model system, hybrids between female Japanese and male Chinese toads were newly generated from 3 pairs of parents and pathological changes in their kidneys were examined sequentially over 6 years. In hybrids from 2 of the 3 pairs, bilateral polycystic kidney developed at a high frequency from 3 months after fertilization, this being associated with the emergence of atypical, premalignant-appearing cells in proximal tubules. Papillary lesions developed after 12 months and renal cell carcinomas after 48 months. Such pathological changes were never seen in non-hybrid Chinese or Japanese toads. Electron microscopy showed no evidence of any viral participation. This unique toad model may prove useful for investigation of the underlying mechanisms of genetically determined renal cell carcinogenesis.
authors.affiliation: Department of Pathology, The Cancer Institute of Japanese Foundation for Cancer Research, Tokyo, Japan.
authors.forename: Prince
authors.initials: P
authors.lastname: Masahito
authors.forename: Midori
authors.initials: M
authors.lastname: Nishioka
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Kondo
authors.forename: Ieharu
authors.initials: I
authors.lastname: Yamazaki
authors.forename: Kimie
authors.initials: K
authors.lastname: Nomura
authors.forename: Yo
authors.initials: Y
authors.lastname: Kato
authors.forename: Haruo
authors.initials: H
authors.lastname: Sugano
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kitagawa
mesh_terms: D000818:Animals; D002025:Bufonidae; D002292:Carcinoma, Renal Cell / Q000473:pathology / Q000662:veterinary*; D002678:Chimera; D002681:China; D003433:Crosses, Genetic; D004195:Disease Models, Animal; D005260:Female; D007564:Japan; D007680:Kidney Neoplasms / Q000473:pathology / Q000662:veterinary*; D037102:Lectins / Q000737:chemistry; D008297:Male; D007690:Polycystic Kidney Diseases / Q000473:pathology / Q000662:veterinary*
chemical_list: D037102:Lectins