-  INCLUSION CRITERIA:

        Patients with the following types of histologically documented solid tumors:

          -  ER +/PR+, ER+/PR-, or ER-/PR+ breast cancer

          -  Gynecologic tumors (endometrial, ovarian, uterine, fallopian tube, peritoneal, etc.)

          -  Desmoid tumors

          -  Tumors that are ER+ or PR+ by immunohistochemistry (including low-level expression)
             such as non-small cell lung, colorectal, and prostate

        Patients with breast cancer must have had at least one prior chemotherapy regimen for
        metastatic disease. Additionally, patients with breast cancer must have received prior
        tamoxifen and/or aromatase inhibitor therapy (if postmenopausal) with at least one hormonal
        regimen in the metastatic setting. Patients with HER2+ breast cancer must have progressed
        after at least one prior HER2-directed regimen (trastuzumab, lapatinib) for metastatic
        disease.

        All other patients must have disease that has progressed following at least one line of
        standard therapy. Prior therapy with tamoxifen is allowed.

        Patients enrolled based on tumor ER/PR status must have ER/PR status confirmed by the
        Laboratory of Pathology, NIH. ER/PR status will be determined on a metastatic site, if
        possible; otherwise, the original site or available tissue will be acceptable.

        Patients must have recovered to at least eligibility levels following any display of
        adverse events and/or toxicity due to prior chemotherapy or biologic therapy. They must not
        have had hormonal therapy, chemotherapy or biologic therapy within 4 weeks prior to
        entering the study (6 weeks for nitrosoureas or mitomycin C, or UCN-01). Patients must be
        greater than or equal 2 weeks since any prior administration of study drug in a Phase 0
        study (also referred to as an "early Phase I study" or "pre-Phase I study" where a
        sub-therapeutic dose of drug is administered) at the PI's discretion. Patients must be
        greater than or equal to 4 weeks since any prior radiation or major surgery. However,
        patients receiving bisphosphonates or therapeutic anticoagulation are eligible for this
        trial.

        Age greater than or equal 18 years

        The Eastern Cooperative Oncology Group (ECOG) performance status less than or equal to 2

        Life expectancy > 3 months

        Patients must have normal or adequate organ and marrow function as defined below:

        Absolute neutrophil count greater than or equal to 1,500/microL

        Platelets greater than or equal to 100,000/micorL

        Total bilirubin within less than or equal to 1.5 times institutional upper limit of normal

        AST (SGOT)/ALT (SGPT) less than or equal to 2.5 times institutional upper limit of normal

        Creatinine < 1.5 times upper limit of normal

        OR

        Creatinine clearance greater than or equal to 60 mL/min/1.73 m(2) for patients with
        creatinine levels greater than or equal to 1.5 times upper limit of normal.

        The effects of Z-endoxifen on the developing human fetus are unknown. For this reason,
        women of childbearing potential and men must agree to use adequate nonhormonal
        contraception (barrier method of birth control or abstinence) prior to study entry, for the
        duration of study participation, and for 2 months after discontinuation from the study.
        Women of childbearing potential must have a negative pregnancy test in order to be
        eligible. Should a woman become pregnant or suspect she is pregnant while participating in
        this study, she should inform her treating physician immediately. Because there is an
        unknown but potential risk for adverse events in nursing infants secondary to treatment of
        the mother with Z-endoxifen, breastfeeding should be discontinued if the mother is treated
        with Z-endoxifen.

        Ability to understand and the willingness to sign a written informed consent document.

        EXCLUSION CRITERIA:

        Patients receiving any other investigational agents.

        Patients with known brain metastases are excluded from this clinical trial, with the
        exception of patients whose brain metastatic disease status has remained stable for greater
        than or equal to 3 months after treatment of the brain metastases, without steroids or
        anti-seizure medications. These patients may be enrolled at the discretion of the principal
        investigator.

        Patients with clinically significant illnesses which could compromise participation in the
        study, including, but not limited to, uncontrolled infection, uncontrolled diabetes,
        uncontrolled hypertension, symptomatic congestive heart failure, unstable angina pectoris,
        myocardial infarction within the past 6 months, uncontrolled cardiac arrhythmia,
        stroke/cerebrovascular accident within the past 6 months, or psychiatric illness/social
        situations that in the investigator s opinion would make it undesirable for the patient to
        participate in the trial, or which would jeopardize compliance with the protocol.

        Patients with untreated spinal cord metastases or metastases close to vital organs (as
        determined by the principal investigator) are excluded because of the risk of hormonal
        flare.

        Patients with a history of deep vein thrombosis must be on anti-coagulation therapy prior
        to enrollment. Patients requiring prophylactic anti-coagulation are eligible.