Abstract 3293: p53 suppresses type II endometrial carcinomas in mice and governs endometrial tumour aggressiveness in humans

Type II endometrial carcinomas are a highly aggressive group of tumour subtypes that are frequently associated with inactivation of the TP53 tumour suppressor gene. We show that mice with endometrium-specific deletion of Trp53 initially exhibited histological changes that are identical to known precursor lesions of type II endometrial carcinomas in humans and later developed carcinomas representing all type II carcinoma subtypes. The PI3K-Akt-mTOR signalling pathway was frequently activated in these precursor lesions and tumours, suggesting a genetic cooperation between this pathway and Trp53 deficiency in tumour initiation. Consistent with this idea, immunohistochemical analyses of 521 human endometrial carcinomas identified frequent mTOR pathway activation in type I as well as type II endometrial carcinoma subtypes and mTOR pathway activation and p53 expression each independently predicted poor patient survival. We suggest that molecular alterations in p53 and the PI3K-mTOR pathway play different roles in the initiation of the different endometrial cancer subtypes, but that combined p53 inactivation and PI3K-mTOR pathway activation are unifying pathogenic features among histologically diverse subtypes of late stage aggressive endometrial tumours. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3293. doi:1538-7445.AM2012-3293