title: Gender differences in the incidence of background and chemically induced primary pulmonary neoplasms in B6C3F1 mice: a retrospective analysis of the National Toxicology Program (NTP) carcinogenicity bioassays.
abstract: The National Toxicology Program (NTP) database of technical reports on carcinogenicity bioassays has been interrogated for the incidence of primary pulmonary neoplasms in B6C3F1 mice. A total of 170 study reports were selected, from studies that completed the in-life phase during 1983-2007, which included neoplasm incidence data for 180 control groups comprising both male and female mice. The incidence (median and inter-quartile range) of males with alveolar/bronchiolar adenoma was 16% (12-20%), and for females it was 5% (2-8%); the incidence of males with alveolar/bronchiolar carcinoma was 8% (4-12%), and for females it was 2% (0-4%); and the incidence of males with combined alveolar/bronchiolar adenoma or carcinoma was 24% (18-30%), and for females it was 8% (6-12%). Comparing the incidence of animals bearing these lesions on a per study basis showed the median incidence in males to be 3.0-fold, 2.0-fold, and 2.8-fold higher than in females. The incidence of other primary pulmonary neoplasms was <10% of the alveolar/bronchiolar neoplasms. Comparison of gender-specific response to lung tumorigens showed that the increase in incidence of tumors above control levels was greater in females than in males.
authors.affiliation: Toxicology and Environmental Research and Consulting, Dow Europe GmbH, Horgen, Switzerland. Electronic address: nigel.moore@penmanconsulting.com.
authors.forename: Nigel P
authors.initials: NP
authors.lastname: Moore
authors.forename: Lisa G
authors.initials: LG
authors.lastname: McFadden
authors.forename: Bryce D
authors.initials: BD
authors.lastname: Landenberger
authors.forename: Johnson
authors.initials: J
authors.lastname: Thomas
mesh_terms: D000818:Animals; D001681:Biological Assay; D015197:Carcinogenicity Tests; D005260:Female; D015994:Incidence; D008175:Lung Neoplasms / Q000139:chemically induced / Q000453:epidemiology* / Q000473:pathology; D008297:Male; D051379:Mice; D012189:Retrospective Studies; D012727:Sex Characteristics
keywords: A/B; Adenoma; Alveolar/bronchiolar; B6C3F(1) mouse; BTQ(MF); Carcinoma; GLP; Gender susceptibility; Good Laboratory Practice; Lung; NIH; NIH-07; NIH-31; NTP; NTP-2000; National Institutes of Health; National Toxicology Program; alveolar/bronchiolar; male-to-female background tumor quotient; rodent maintenance diets