title: Spontaneous and urethan-induced tumor incidence in B6C3F1 versus B6CF1 mice.
abstract: The incidences of spontaneous tumors of the murine hybrids (C57BL/6J X C3Hf)F1 (B6C3F1) and (C57BL/6J X BALB/c)F1 (B6CF1) were compared in untreated mice kept until 110 weeks of age. Male B6C3F1 and B6CF1 mice had respectively 16% and 20% incidence of lymphomas, 26% and 4% of liver tumors and 12% and 22% of lung tumors. Among B6C3F1 and B6CF1 females, a 36% and 12% incidence of lymphomas, a 6% and zero incidence of liver tumors, and a 4% and 16% of lung tumors were observed. A few other tumors were seen in both hybrids. Groups of male and female mice of the 2 hybrids received 5 i.p. injections of 1000 mg/kg urethan once every other day starting at 10 days of age, and were kept under observation until 65-80 weeks of age. Treated B6C3F1 mice had an earlier mortality than B6CF1 mice due to tumor development. The statistical analysis, allowing for survival, showed a significantly higher lymphoma incidence in male and female B6C3F1 than B6CF1 mice, which had instead a higher incidence of lung tumors. Hepatocellular tumors were seen in both sexes of the 2 hybrids, with a higher frequency in B6C3F1 mice. Male mice of both hybrids had a higher incidence of liver tumors than females.
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D006824:Hybridization, Genetic; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced; D008175:Lung Neoplasms / Q000139:chemically induced; D008223:Lymphoma / Q000139:chemically induced; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009374:Neoplasms, Experimental / Q000139:chemically induced*; D012737:Sex Factors; D014520:Urethane / Q000633:toxicity*
chemical_list: D014520:Urethane