Patients on this study are being asked to allow the researchers to take a piece of some normal endometrial tissue and tumor tissue. No additional endometrial tissue will be taken for this study other than what is surgically indicated to resect the patients tumor completely. Prior to this surgery, patients will receive one more dose of L9NC in the outpatient clinic in the same manner as the other L9NC treatments they have received. After the tumor has been removed, the tissue will be examined by a pathologist, who will take what is needed to diagnose the residual disease. What is not needed for patient care will be used for research. A piece of the tumor and some normal endometrial tissue surrounding the tumor will be sent to the Investigational Drug Program laboratory, which is located in the Cancer Center, to measure the amount of drug that is left in the patients tumor. The patients tissue will be kept until all tissues are collected from all patients, which could take up to 10 years. The tissue will not be used for any other purpose. The samples will be labeled with the patients initials.