Interlaboratory comparison of short-term carcinogenicity studies using CB6F1-rasH2 transgenic mice.

In order to evaluate a short-term carcinogenicity testing system using CB6F1 -Tg rasH2 (rasH2-Tg) mice carrying a human prototype c-Ha-ras gene, 26-week studies were conducted in 12 different facilities as a part of an International Life Science Institute Health and Environmental Science Institute (ILSI HESI) international collaborative project. In each study N-methyl-N-nitrosourea (MNU) was administered to a separate group of rasH2-Tg mice by single intraperitoneal injection (75 mg/kg) as a positive control. We herein have summarized the mortality, body weight change, and neoplastic and nonneoplastic lesions detected in these positive control groups as representative historical positive control data.

Twenty-six-Week carcinogenicity study of chloroform in CB6F1 rasH2-transgenic mice.

The carcinogenic potential of chloroform was evaluated in a short-term carcinogenicity testing system using CB6F1 rasH2-Tg (rasH2-Tg) mice. Chloroform was administered to rasH2-Tg males at doses of 28, 90, or 140 mg/kg and rasH2-Tg females at 24, 90, or 240 mg/kg by oral gavage for 26 weeks. Wild-type (non-Tg) male and female mice received doses of 140 mg/kg and 240 mg/kg, respectively.