2-Methoxyestradiol in Treating Patients With Advanced Solid Tumors

Inclusion Criteria: * Histologically confirmed solid tumor that is clinically unresectable * No known standard therapy that is potentially curative or definitely capable of extending life expectancy * Patients with multiple myeloma may be enrolled to expansion cohort once the recommended phase II dose is established * Tumor amenable to serial biopsy * No bone metastases as only site of disease * No CNS metastases * Performance status - ECOG 0-2 * At least 12 weeks * Absolute neutrophil count at least 1,500/mm\^3 * Platelet count at least 100,000/mm\^3 * Hemoglobin at least 10.0 g/dL * Bilirubin normal * AST no greater than 2.5 times upper limit of normal (ULN) * Creatinine no greater than 1.5 times ULN * No New York Heart Association class III or IV heart disease * Adequate oral intake * No malabsorption syndrome * No disease of terminal small bowel * No dysphagia or other condition that would interfere with ability to swallow intact capsules * No clinical contraindications (e.g., anticoagulant therapy) to biopsy * No uncontrolled infection * No seizure disorder * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * More than 4 weeks since prior biologic therapy * More than 4 weeks since prior immunotherapy * No concurrent immunotherapy * More than 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin) and recovered * No concurrent chemotherapy * No concurrent megestrol * More than 4 weeks since prior radiotherapy * No prior radiotherapy to more than 25% of bone marrow * No concurrent radiotherapy * No prior extensive resection of terminal small bowel * No prior major resection of the stomach or proximal small bowel * No other concurrent ancillary investigational therapy