HOXB6 and neoplasm: These findings are similar to our observation that BMI1 expression is down-regulated in siHOXB6 and siHOXB6B8 cells which correlates with the induction of senescence, repression of tumor cell proliferation, and up-regulation of the tumor suppressor CDKN2A. Moreover, HOXB6 and HOXB8 expression is decreased in gemcitabine-treated PDAC cells and expression levels affected PDAC cell sensitivity to gemcitabine treatment further supporting that HOX genes act as key regulators to prevent tumor senescence and treatment efficacy in PDAC.