Some cases of endometrial cancer are dependent on estrogen for their growth. Letrozole blocks
estrogen production in the body. The purpose of this study is to determine if the
investigators can predict which patients might benefit from Letrozole treatment by studying
the many different forms of the estrogen receptor molecule that exist within the cancer
tissues. To participate in this study, the patients must be 40 years of age or older and have
biopsy-proven endometrial carcinoma, either well differentiated or moderately differentiated
forms. Also, to be eligible to participate in this study, the patients need to be healthy
enough to have a hysterectomy. If the patients are less than age 60, they will need a blood
test (FSH) to confirm that they have gone into menopause.