Melphalan and Autologous Stem Cell Transplant Followed By Bortezomib and Dexamethasone in Treating Patients With Previously Untreated Systemic Amyloidosis

DISEASE CHARACTERISTICS: * Histologically confirmed amyloidosis * Diagnosed within the past 12 months * Clonal plasma cell disorder, as demonstrated by any of the following: * Presence of M-protein in serum and/or urine by immunofixation and/or serum free light chain assay * Clonal population of plasma cells in the bone marrow based on kappa/lambda staining of a marrow biopsy * Negative genetic testing for hereditary forms of amyloidosis * No amyloid-specific syndrome (e.g., carpal tunnel syndrome or skin purpura) as the only evidence of disease * Vascular amyloidosis only in a bone marrow biopsy specimen or in plasmacytoma is not indicative of systemic amyloidosis * No advanced cardiac amyloidosis * Must have symptomatic involvement of no more than 2 of the following visceral organ systems: * Kidneys * Liver/gastrointestinal * Peripheral/autonomic nervous system * Heart * No persistent pleural effusions * No clinically overt multiple myeloma with \> 30% plasma cells in the bone marrow or lytic bone lesions * Able to undergo autologous stem cell transplantation PATIENT CHARACTERISTICS: * SWOG performance status 0-3 * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * Bilirubin \< 2.0 mg/dL * Creatinine clearance \< 51 mL/min allowed * LVEF \> 45% by echocardiogram * No New York Heart Association class III-IV congestive heart failure * No history of cardiac syncope * No recurrent symptomatic arrhythmias * No oxygen-dependent restrictive cardiomyopathy * No myocardial infarction within the past 6 months * Pulmonary diffusion capacity \> 50% predicted by pulmonary function testing * No uncontrolled infection * No other active malignancy, except for any of the following: * Adequately treated basal cell or squamous cell skin cancer * In situ cervical cancer * Adequately treated stage I cancer from which the patient is currently in complete remission * Any other cancer from which the patient has been disease-free for 5 years * No hypersensitivity to bortezomib, boron, or mannitol * No HIV positivity * No serious medical or psychiatric illness that would preclude study compliance PRIOR CONCURRENT THERAPY: * At least 14 days since prior investigational drugs * No prior therapy for monoclonal plasma disease