title: Spontaneous vulvar papillomas in a colony of mice used for pancreatic cancer research.
abstract: Mice in a colony used for pancreatic cancer research and maintained in a barrier animal facility presented with vulvar masses. A census and examination of all colony animals was conducted on 17 February 2006; line, gender, and mass location were recorded; a slide caliper was used to measure the width, length, and height of each mass; and the volume of each mass was calculated. Progeny female mice from crossbreeding of the B6.FVB-Tg(Ipf1-cre)1Tuv and B6;129-Kras2tm4Tyj (KRAS(G12D/+)) strains presented with external vulvar and periauricular papillomas. The papillomas were present in 41.2% of all female crossbred mice and ranged in size from 8 to 36 mm3. Age of mice and tumor size were not correlated. Compared with the B6.FVB-Tg(Ipf1-cre)1Tuv line, the crossbred female mice were more likely to have a vulvar mass, with an odds ratio of 29.3, 95% confidence interval (1.5, 563.9) and a positive predictive value of 42.9%. Diagnostic evaluation, including electron microscopy, light microscopy, serology, and bacteriology, did not reveal a viral or other infectious etiology. Therefore, we speculate that interaction between the genetic background of the mice and the introduced Kras oncogene may be responsible for these papillomas.
authors.affiliation: Department of Comparative Medicine, Mayo Clinic, Scottsdale, AZ, USA. gades.naomi@mayo.edu
authors.forename: Naomi M
authors.initials: NM
authors.lastname: Gades
authors.forename: Akihiro
authors.initials: A
authors.lastname: Ohash
authors.forename: Lisa D
authors.initials: LD
authors.lastname: Mills
authors.forename: Matt A
authors.initials: MA
authors.lastname: Rowley
authors.forename: Kelly S
authors.initials: KS
authors.lastname: Predmore
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Marler
authors.forename: Fergus J
authors.initials: FJ
authors.lastname: Couch
mesh_terms: D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D005260:Female; D051379:Mice; D046529:Microscopy, Electron, Transmission; D010190:Pancreatic Neoplasms / Q000473:pathology*; D010212:Papilloma / Q000473:pathology*; D016133:Polymerase Chain Reaction; D014846:Vulvar Neoplasms / Q000473:pathology*
chemical_list: D017931:DNA Primers