Endometrial cancer; Clonal evolution; MutationCáncer endometrial; Evolución clonal; MutaciónCàncer d'endometri; Evolució clonal; MutacióAnalyzing different tumor regions by next generation sequencing allows the assessment of intratumor genetic heterogeneity (ITGH), a phenomenon that has been studied widely in some tumor types but has been less well explored in endometrial carcinoma (EC). In this study, we sought to characterize the spatial and temporal heterogeneity of 9 different ECs using whole-exome sequencing, and by performing targeted sequencing validation of the 42 primary tumor regions and 30 metastatic samples analyzed. In addition, copy number alterations of serous carcinomas were assessed by comparative genomic hybridization arrays. From the somatic mutations, identified by whole-exome sequencing, 532 were validated by targeted sequencing. Based on these data, the phylogenetic tree reconstructed for each case allowed us to establish the tumors’ evolution and correlate this to tumor progression, prognosis, and the presence of recurrent disease. Moreover, we studied the genetic landscape of an ambiguous EC and the molecular profile obtained was used to guide the selection of a potential personalized therapy for this patient, which was subsequently validated by preclinical testing in patient-derived xenograft models. Overall, our study reveals the impact of analyzing different tumor regions to decipher the ITGH in ECs, which could help make the best treatment decision.We thank all those at the Translational Research Laboratory of the MD Anderson Cancer Center Madrid for their invaluable help with this study. Tissue samples were obtained with the support of the MD Anderson Foundation Biobank (record number B.0000745, ISCIII National Biobank Record), the “Xarxa Catalana de Bancs de Tumors” and “Plataforma de Biobancos” ISCIII (PT13/0010/0014, B.000609). This study has been supported by the Spanish Ministry of Economy and Innovation (PID2019-104644RB-I00 (GMB), the Instituto de Salud Carlos III (ISCIII, CIBERONC, CB16/12/00295 - GMB-, CB16/12/00328 -EC, AGM- and CB16/12/00231 -XMG- [all partly supported by FEDER funds]) and by the AECC Scientific Foundation (FC_AECC PROYE19036MOR -GMB- and Coordinated groups 2018 -XMG, AGM, GMB-). SO is funded by an AECC-postdoctoral grant (2020). JSR-F and BW are funded in part by the Breast Cancer Research Foundation and in part by the NIH/NCI P50 CA247749 01 grant. Research reported in this publication was supported in part by a Cancer Center Support Grant of the NIH/NCI (Grant No. P30CA008748; MSK). We thank the Eurofins Megalab laboratory for helping us to perform the analysis of DNA HPV detection
