TP53 and leiomyosarcoma: Although this may potentially explain the high frequency of ovarian leiomyosarcomas observed, a previous study employing intrabursal adenovirus-Cre-recombinase mediated inactivation of LoxP-flanked sequences in p53LoxP/LoxP;RbLoxP/LoxP mice reported a high prevalence of ovarian carcinomas rather than leiomyosarcomas [19], suggesting the explanation may be more complicated than just relative tissue susceptibility in mice with p53 mutations.