Inclusion Criteria

DISEASE CHARACTERISTICS:

- Diagnosis of indolent B-cell non-Hodgkin's lymphoma of 1 of the following subtypes:

- Follicular (grade 1, 2, or 3)

- Marginal zone (extranodal, nodal, or splenic)

- CD20-positive disease

- Relapsed or progressive disease after prior anti-neoplastic therapy, as indicated by
1 of the following:

- New lesions

- Objective evidence of progression of existing lesions

- Complete response ≥ 6 months in duration after prior rituximab therapy* NOTE: *For
patients who were previously treated with a regimen that included rituximab

- At least 1 measurable lymph node mass > 1.5 cm in 2 perpendicular dimensions that has
not been irradiated OR that has progressed since prior radiotherapy

- No active CNS lymphoma

PATIENT CHARACTERISTICS:

Age

- 18 and over

Performance status

- Karnofsky 50-100% OR

- ECOG 0-2

Life expectancy

- Not specified

Hematopoietic

- Absolute neutrophil count ≥ 1,000/mm^3

- Platelet count ≥ 50,000/mm^3

Hepatic

- AST and ALT ≤ 3 times upper limit of normal (ULN)

- Bilirubin ≤ 2 times ULN

Renal

- Creatinine ≤ 2 mg/dL OR

- Creatinine clearance ≥ 30 mL/min

Immunologic

- No known anaphylaxis or immunoglobulin E-mediated hypersensitivity to murine proteins
or to any component of rituximab, including polysorbate 80 and sodium citrate
dihydrate

- No active systemic infection requiring treatment

- No history of allergic reaction attributable to compounds containing boron or
mannitol

Other

- No peripheral neuropathy or neuropathic pain ≥ grade 2

- No other malignancy within the past 5 years except completely resected basal cell or
squamous cell skin cancer or an in situ malignancy

- Previously diagnosed prostate cancer allowed provided the following criteria are
met:

- T1-2a, N0, M0 disease AND Gleason score ≤ 7 AND prostate specific antigen
(PSA) ≤ 10 ng/mL before initial therapy

- Treated with definitive curative therapy (i.e., prostatectomy or
radiotherapy) within the past 2 years

- No clinical evidence of prostate cancer AND undetectable PSA (for
prostatectomy patients) or PSA < 1 ng/mL (for patients who did not undergo
prostatectomy)

- No serious medical or psychiatric illness that would preclude study participation

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy

- See Disease Characteristics

- More than 10 weeks since prior radioimmunoconjugates or toxin immunoconjugates (e.g.,
ibritumomab tiuxetan or iodine I 131 tositumomab)

- More than 4 weeks since prior rituximab, alemtuzumab, or other unconjugated
therapeutic antibody

- No concurrent prophylactic bone marrow growth factors (e.g., filgrastim [G-CSF],
sargramostim [GM-CSF], or epoetin alfa) during course 1 of study therapy

Chemotherapy

- More than 6 weeks since prior nitrosoureas

- No concurrent cisplatin

Endocrine therapy

- No concurrent corticosteroids (e.g., dexamethasone) except prednisone ≤ 15 mg/day or
equivalent for adrenal insufficiency

Radiotherapy

- See Disease Characteristics

- See Biologic therapy

- More than 3 weeks since prior radiotherapy

- No concurrent radiotherapy

Surgery

- More than 2 weeks since prior major surgery

Other

- Recovered from all prior therapy

- No prior bortezomib

- More than 3 weeks since prior antineoplastic therapy

- More than 3 weeks since prior experimental therapy

- No other concurrent antineoplastic therapy

- No other concurrent investigational agents

- Concurrent participation in a non-treatment study allowed provided it does not
interfere with participation in this study