Inclusion Criteria:

- Histological confirmed diagnosis of grade I or II adenocarcinoma of the endometrium

- Must be obese as defined by a body mass index (BMI) greater than or equal to 30 kg/m2

- Candidate for surgical removal of their uterus as part of their endometrial cancer
treatment

- Subjects must have signed informed consent

- Age 45 - 65 years of age

- Electrocorticogram (ECOG) Performance status of 0 - 2

- History of adequate renal, liver, and bone marrow function:

- Hb: (adequate for surgical intervention, with transfusion if necessary) White
Blood Cell (WBC): (normal range)

- Platelets: (180K/cmm)

- Liver Function Test(LFTs): Normal bilirubin (<2.0mg/dL), AST/ALT (2xULN)

- Renal function: creatinine less than 1.4

- Female subjects must either not be of child-bearing potential or must have a negative
urine pregnancy test within 7 days of randomization to Metformin. Subjects are
considered not of child-bearing potential if they are surgically sterile or they are
postmenopausal for greater than 12 months.

Exclusion Criteria:

- Poorly differentiated cancer or any of the high-risk subtypes of endometrial cancer
including serous, clear cell, or carcinosarcoma

- History of diabetes mellitus Type 1 or Type 2.

- Receiving metformin prior to enrollment

- Known hypersensitivity to metformin.

- Unable to swallow and retain oral medication.

- Pregnant or lactating.

- Previous or concurrent malignancies, except non-melanoma skin cancers, unless
curatively treated and with no evidence of recurrence for > 5 years

- If the physician feels that the candidate is not suitable for the study, he/she will
be excluded.

- Currently taking biguanides, sulfonylurea drugs, thiazolidinediones, insulin, or mTOR
or DPP-4 inhibitors or having taken any of these medications during the 12 weeks
prior to study participation.

- Currently taking any non-steroidal anti-inflammatory drugs (NSAIDs) or aspirin and
unable to stop such medications due to a present medical condition.

- Clinical symptoms of gastrointestinal obstruction or bleeding and consideration for
immediate surgery or immediate neoadjuvant chemoradiation.

- History of lactic or other metabolic acidosis.

- Uncontrolled infectious disease.

- History of positivity for human immunodeficiency virus (HIV).

- History of congestive heart failure requiring pharmacologic treatment.

- History of excessive alcohol abuse, defined by a habitual intake of more than three
drinks daily.

- Mal-absorption syndrome, disease affecting gastrointestinal function, or previous
resection of the stomach or small bowel.

- Current use of medications for weight loss.

- Currently taking cimetidine, thiazide diuretics or cephalexin. If a patient needs
some of these agents, alternative agents should be substituted.