Inclusion Criteria

DISEASE CHARACTERISTICS:

- Biopsy-proven Epstein-Barr virus (EBV)-positive malignancy

- Must have tissue analysis to confirm EBV positivity

- Archival tissue ≤ 1 year old may be used

- Any of the following malignancies:

- WHO type II or III nasopharyngeal carcinoma

- Post-transplant lymphoproliferative disorder

- Nasal NK/T-cell lymphoma

- Hodgkin's lymphoma

- Lymphoepithelioma-variant gastric carcinoma

- AIDS-related lymphomas

- Patients with CNS non-Hodgkin's lymphoma must have tumor cells present in
the cerebrospinal fluid (and assessable with lumbar puncture)

- Relapsed or refractory disease

- Must have received and failed all prior potentially curative treatment for
disease

- Eligible only for salvage therapy

- Must have tumor tissue amenable for minimally invasive biopsy (e.g., fine-needle
aspiration or bone marrow biopsy)

- No brain tumors not amenable to biopsy

- CNS metastases allowed provided ≥ 2 weeks since prior radiotherapy

PATIENT CHARACTERISTICS:

- ECOG performance status 0-2

- Life expectancy ≥ 3 months

- Absolute granulocyte count ≥ 500/mm³

- Platelet count ≥ 50,000/mm³

- Bilirubin ≤ 1.5 times upper limit of normal

- Creatinine ≤ 2.0 mg/dL OR creatinine clearance ≥ 40 mL/min

- Recovered from uncontrolled intercurrent illness, including, but not limited to, any
of the following:

- Ongoing or active infection

- Symptomatic congestive heart failure

- Unstable angina pectoris

- Cardiac arrhythmia

- Able to take medication orally or by gastrostomy tube

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception prior to, during, and for 90 days
after completion of study treatment

- No uncontrolled grade 1 symptomatic diarrhea (i.e., > 3 stools/day)

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

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- Concurrent cerebrospinal fluid drugs allowed

- No concurrent zidovudine for HIV-positive patients