A Randomized Surgical Window Pilot Investigation of the Relationship of Short Term Medroxyprogesterone Acetate (NSC #26386) Compared to Medroxyprogesterone Acetate Plus Entinostat (NSC #706995) on the Morphologic, Biochemical, and Molecular Changes in Primary Endometrioid Adenocarcinoma of the Uterine Corpus

• Patients must have a histologically proven diagnosis of endometrioid endometrial adenocarcinoma by endometrial curettage or biopsy within 8 weeks prior to registration; central pathology review will be required as part of the study but not for registration purposes

• History/physical examination within 42 +/- 5 days of planned surgical procedure (18-21 days from day 1); further protocol-specific assessments

• The trial is open only to women with primary endometrioid adenocarcinoma of the uterine corpus (all histologic grades and stages) who are planned and appropriate for primary surgical treatment to include removal of the uterine corpus via any surgical modality; the patient must be considered a suitable surgical candidate

• Patients must have an Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, 2, or 3 within 28 days prior to registration

• Formalin-fixed, paraffin-embedded tumor tissue from the biopsy or curettage must be submitted along with the corresponding pathology report

• Platelets \>= 100,000/ul

• Granulocytes (ANC) \>= 1,500/ul

• Creatinine =\< 1.6 mg/dl

• Serum glutamate pyruvate transaminase (SGPT) (alanine aminotransferase \[ALT\]) =\< 3 x upper limits of normal

• Bilirubin within institutional normal limits

• The patient must provide study-specific informed consent and authorization permitting release of personal health information prior to study entry

• Any patients of childbearing potential must have a negative pregnancy test