title: Trend analysis of body weight parameters, mortality, and incidence of spontaneous tumors in Tg.rasH2 mice.
abstract: Carcinogenicity studies have been performed in conventional 2-year rodent studies for at least 3 decades, whereas the short-term carcinogenicity studies in transgenic mice, such as Tg.rasH2, have only been performed over the last decade. In the 2-year conventional rodent studies, interlinked problems, such as increasing trends in the initial body weights, increased body weight gains, high incidence of spontaneous tumors, and low survival, that complicate the interpretation of findings have been well established. However, these end points have not been evaluated in the short-term carcinogenicity studies involving the Tg.rasH2 mice. In this article, we present retrospective analysis of data obtained from control groups in 26-week carcinogenicity studies conducted in Tg.rasH2 mice since 2004. Our analysis showed statistically significant decreasing trends in initial body weights of both sexes. Although the terminal body weights did not show any significant trends, there was a statistically significant increasing trend toward body weight gains, more so in males than in females, which correlated with increasing trends in the food consumption. There were no statistically significant alterations in mortality trends. In addition, the incidence of all common spontaneous tumors remained fairly constant with no statistically significant differences in trends.
authors.affiliation: BioReliance By SAFC, Rockville, MD, USA.
authors.forename: Madhav G
authors.initials: MG
authors.lastname: Paranjpe
authors.affiliation: BioReliance By SAFC, Rockville, MD, USA.
authors.forename: Melissa D
authors.initials: MD
authors.lastname: Denton
authors.affiliation: BioSTAT Consultants, Inc, Portage, MI, USA.
authors.forename: Tom
authors.initials: T
authors.lastname: Vidmar
authors.affiliation: BioReliance By SAFC, Rockville, MD, USA reem.elbekai@bioreliance.com.
authors.forename: Reem H
authors.initials: RH
authors.lastname: Elbekai
mesh_terms: D000818:Animals; D001835:Body Weight; D015197:Carcinogenicity Tests; D004435:Eating; D005260:Female; D015994:Incidence; D008297:Male; D008822:Mice, Transgenic; D009026:Mortality / Q000639:trends; D009369:Neoplasms / Q000662:veterinary
keywords: Tg.rasH2 mice; body weights; carcinogenicity; trends