Inclusion Criteria

DISEASE CHARACTERISTICS:

- Diagnosis of mantle cell lymphoma

- Stable disease after first- or second-line chemotherapy

- No uncontrolled cerebral or leptomeningeal disease

PATIENT CHARACTERISTICS:

- WHO performance status 0-2

- Life expectancy ≥ 3 months

- Age ≥ 60 years or patients ≥ 40 and < 60 years who are not suitable for high-dose
chemotherapy followed by autologous stem cell transplantation or allogeneic stem cell
transplantation

- ANC ≥ 1,500/mm^3

- Platelet count ≥ 100,000/mm^3

- Hemoglobin > 9 g/dL

- Serum creatinine ≤ 1.5 times upper limit of normal (ULN)

- SGPT and SGOT ≤ 3 times ULN

- Bilirubin ≤ 1.5 times ULN

- No other malignancies within the past 3 years except treated cervical carcinoma or
basal cell cancer

- No other serious or non-controlled illnesses (e.g., diabetes mellitus, uncontrolled
hypertension, serious infections, serious malnutrition, unstable angina pectoris,
weak heart, myocardial infarction within the past 6 months, chronic liver illness,
active ulceration in the gastrointestinal tract, psychiatric illness)

- No known HIV infection

- No gastrointestinal disturbances that could influence the absorption of everolimus
and cause short-intestine syndrome (e.g., atrophic gastritis)

- No coagulation or bleeding diatheses

- Not pregnant or nursing

- Fertile patients must use effective contraception

- Patients must have complied with their previous drug prescription

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- See Patient Characteristics

- Recovered from all prior therapy

- At least 2 weeks since prior surgery, radiotherapy, or systemic antitumor therapy

- More than 4 weeks since prior experimental medication

- No chronic therapy with systemic steroids or other immunosuppressants except
rituximab

- No prior organ transplantation

- No therapy with vitamin K antagonist, except low-dose coumarin

- No prior mTOR inhibitors