Ectopic expression of the CR-1 transgene in mammary glands induced mammary hyperplasia and adenocarcinoma in the WAP-CR-1 or MMTV-CR-1 transgenic mice [15, 20] and leiomyosarcoma of the uterus in the MMTV-CR-1 transgenic mice [21]. This evidence concerns the gene CR1 and leiomyosarcoma of the corpus uteri.