PMC:13902 / 22278-23489 JSONTXT

{"project":"Colil","denotations":[{"id":"T58","span":{"begin":692,"end":694},"obj":"2936526"},{"id":"T59","span":{"begin":688,"end":689},"obj":"8062253"},{"id":"T60","span":{"begin":690,"end":691},"obj":"421218"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/docs/sourcedb/PubMed/sourceid/"}],"text":"Chemopreventive efficacy\nPalpable mammary tumors were first detected after approximately 35 days following initation with NMU, and by 70 days incidence had reached 100% in rats not treated with chemopreventive agents (Fig. 1a). Tamoxifen, alone or in combination with retinoids, decreased tumor incidence by more than 70% by the end of the study, whereas 9cRA alone decreased it by 50%. 4-HPR alone had a relatively modest effect on tumor incidence in the present study. However, it significantly decreased tumor multiplicity (Fig. 1b) indicating that the dose used was efficacious. These incidence and multiplicity data are consistent with previously published studies using this model [2,4,34]. The mean weights of the rats in the various experimental groups differed by less than 10% from those of rats not treated with a chemopreventive agent, except for the rats treated with a combination of tamoxifen and 4-HPR, in which the mean weight was approximately 15% lower than the that in untreated group by the end of the study (Fig. 1c). This suggests that there was minimal toxicity associated with the chemopreventive intervention, except in the tamoxifen + 4-HPR group, in which mild toxicity was observed."}