Bortezomib and Gemcitabine in Treating Patients With Relapsed Mantle Cell Lymphoma

DISEASE CHARACTERISTICS: * Histologically confirmed mantle cell lymphoma * Relapsed disease * Not refractory to prior therapy * Must have received 1-3 prior systemic chemotherapy regimens AND has had no disease progression while receiving chemotherapy or within 1 month of last dose of most recent therapy * Clinically and/or radiologically documented disease * At least 1 site of disease must be bidimensionally measurable by CT scan or MRI with ≥ 1 lesion meeting 1 of the following criteria: * Lymph nodes ≥ 1.5 cm x 1.5 cm by spiral CT scan * Non-nodal lesion ≥ 1 cm x 1 cm by MRI, CT scan, or physical exam * No nonmeasurable disease only * No preexisting ascites or pleural effusion ≥ grade 2 * No known CNS involvement by lymphoma PATIENT CHARACTERISTICS: * ECOG performance status 0-2 * Life expectancy ≥ 12 weeks * Absolute granulocyte count ≥ 1,500/mm³ * Platelet count ≥ 75,000/mm³ * Creatinine ≤ 1.5 times upper limit of normal (ULN) * Bilirubin ≤ 1.5 times ULN * AST or ALT ≤ 2.5 times ULN * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * LVEF ≥ 45% by echocardiogram or MUGA * No history of allergic reactions attributed to compounds containing boron or mannitol * No preexisting edema ≥ grade 2 * No preexisting neuropathy (sensory and/or pain) ≥ grade 2 * No preexisting shortness of breath ≥ grade 2 * No history of other malignancies, except adequately treated nonmelanoma skin cancer, curatively treated in situ cancer of the cervix, or other solid tumors curatively treated with no evidence of disease for ≥ 5 years * No other serious illness or medical condition that would preclude compliance with study requirements, including any of the following: * Serious uncontrolled infection * Uncontrolled or severe cardiovascular disease, including any of the following: * Myocardial infarction within the past 6 months * New York Heart Association class III-IV heart failure * Uncontrolled angina * Clinically significant pericardial disease * Cardiac amyloidosis * Significant neurological disorder PRIOR CONCURRENT THERAPY: * See Disease Characteristics * At least 6 weeks since prior chemotherapy * No prior radioactive monoclonal antibody therapy * No prior bortezomib * No prior investigational therapy (except for flavopiridol) * No prior radiotherapy to \> 25% of functioning bone marrow * At least 4 weeks since prior radiotherapy and recovered * Low-dose, nonmyelosuppressive radiotherapy may be allowed * At least 2 weeks since prior major surgery * No other concurrent anticancer therapy * No concurrent corticosteroids * No other concurrent cytotoxic chemotherapy * No other concurrent investigational agents