title: Occurrence of Spontaneous Tumors in the Central Nervous System (CNS) of F344 and SD Rats.
abstract: In order to accurately assess the carcinogenicity of chemicals with regard to rare tumors such as rat CNS tumors, sufficient information about spontaneous tumors are very important. This paper presents the data on the type, incidence and detected age of CNS tumors in F344/DuCrlCrlj (a total of 1363 males and 1363 females) and Crl:CD(SD) rats (a total of 1650 males and 1705 females) collected from in-house background data-collection studies and control groups of carcinogenicity studies at our laboratory, together with those previously reported in F344 and SD rats. The present data on F344/DuCrlCrlj rats (F344 rats) and Crl:CD(SD) rats (SD rats) clarified the following. (1) The incidences of all CNS tumors observed in F344 rats were less than 1%. (2) The incidences of malignant astrocytoma and granular cell tumor were higher in male SD rats than in female SD rats. (3) The incidences of astrocytoma and granular cell tumor were higher in SD rats than in F344 rats. (4) Among astrocytoma, oligodendroglioma and granular cell tumor, oligodendroglioma was detected at the youngest age, followed by astrocytoma, and ultimately, granular cell tumor developed in both strains. The incidences observed in our study were almost consistent with those previously reported in F344 and SD rats.
authors.affiliation: Hamamatsu Branch of Pathology Division, BOZO Research Center Inc., 164-2 Wada-cho, Higashi-ku, Hamamatsu, Shizuoka 435-0016, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Nagatani
authors.forename: Kayoko
authors.initials: K
authors.lastname: Kudo
authors.forename: Seiki
authors.initials: S
authors.lastname: Yamakawa
authors.forename: Toko
authors.initials: T
authors.lastname: Ohira
authors.forename: Yuko
authors.initials: Y
authors.lastname: Yamaguchi
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Ikezaki
authors.forename: Isamu
authors.initials: I
authors.lastname: Suzuki
authors.forename: Tsubasa
authors.initials: T
authors.lastname: Saito
authors.forename: Toru
authors.initials: T
authors.lastname: Hoshiya
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Tamura
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Uchida
keywords: F344 rat; SD rat; central nervous system tumor; historical control data