show Abstracthide AbstractLoss-of-function mutations of KDM6A, an X chromosome encoded histone H3K27 demethylase, are frequent in a broad spectrum of epithelial and hematopoietic malignancies and contribute to oncogenesis with so far poorly characterized mechanisms. Pancreas specific ablation of Kdm6a in mice accelerated Kras-driven cell transformation and compromised survival in a gender specific manner. Female knockout animals were particularly vulnerable and developed aggressive squamous and quasi-mesenchymal tumors with metastatic potential, as opposed to the males which developed adenocarcinomas and exhibited a better prognosis. Integration of gene expression studies coupled to ChIP-seq profiling of chromatin modifications demonstrated that loss of Kdm6a caused genome-wide remodeling of bivalent promoters and rewiring of enhancer chromatin to repress endodermal fate by activating c-MYC and TP63 dependent transcriptional programs favoring squamous and quasi-mesenchymal differentiation. Overall design: Cell lines established from K6A null murine pancreatic cancer were analyzed by ChIP-seq for epigentic regulators and histone modifications