ARID1A and neoplasm: Of note, similar to the case in endometrial cancer, additional molecular changes are required to collaborate with Arid1a inactivation in transforming mouse ovarian surface epithelium (MOSE), whereas the deletion of Arid1a alone in MOSE is not sufficient to initiate tumor development, as injection of Ad-Cre virus on ovaries in Arid1af/f mice occurs with no gross or microscopic lesions (48).