TP53 and leiomyosarcoma: Interestingly, in a very recent study that used a genetic approach for reproductive tract restricted Cre-recombinase expression by crossing Amhr2-Cre transgenic mice with Brca1LoxP/LoxP and/or p53LoxP/LoxP mice showed that while Cre-mediated recombination of floxed Brca1 and p53 alleles could be demonstrated in the ovaries, fallopian tubes and uteri of compound transgenic mice, the tumors that developed in these mice were all uterine leiomyosarcomas rather than ovarian tumors of any type [42].