Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically or cytologically confirmed solid tumor or lymphoma that is progressive
or refractory to conventional therapy or for which no effective therapy is known

- Priority given to hormone-refractory prostate cancer and melanoma

- No untreated CNS metastases

- Head CT not required in the absence of clinical signs or symptoms but recommended for
metastatic melanoma

PATIENT CHARACTERISTICS:

- Age: 18 and over

- Performance status: ECOG 0-2

- Life expectancy: At least 3 months

- WBC greater than 2,000/mm3 OR absolute neutrophil count greater than 1,500/mm3

- Platelet count greater than 100,000/mm3

- Hemoglobin greater than 9 g/dL

- Bilirubin less than 1.5 mg/dL

- AST/ALT less than 1.5 times normal

- Creatinine less than 2.0 mg/dL

- Obstructive uropathy allowed if relieved by nephrostomy or other appropriate device

- Left ventricular ejection fraction greater than 40% by MUGA or normal by
echocardiogram

- No history of congestive heart failure

- No uncontrolled hypertension (diastolic greater than 110 mm Hg)

- Forced expiratory volume (1 second) greater than 1.5 L/min

- No active infection, including HIV or viral hepatitis

- No active seizure disorder

- No clinical evidence of increased intracranial pressure

- No baseline dementia (mini-mental exam less than 23)

- No autoimmune disease, including systemic lupus erythematosus, scleroderma, or other
connective tissue illness

- No nonmalignant medical or psychiatric problem of sufficient severity to limit full
compliance with study or to pose undue risk

- Not pregnant or nursing

- Adequate contraception required of fertile patients for 2 weeks prior to, during, and
for 3 months after study

- Normal gastrointestinal function with ability to tolerate large intake of oral volume
required for phenylbutyrate administration

- Patients with persistent nausea or moderate to severe anorexia may not be good
candidates for study

PRIOR CONCURRENT THERAPY:

- Fully recovered from all prior therapy

- Prior suramin allowed if serum suramin level less than 50 micrograms/mL at entry

- At least 28 days since chemotherapy

- No prior phenylacetate, phenylbutyrate, or antineoplaston therapy

- The following may be continued during study:

- Luteinizing hormone-releasing hormone agonist with evidence of tumor progression
(e.g., rising prostate-specific antigen, new lesions on bone scan) despite therapy

- Adrenal steroid replacement (if needed)

- Dexamethasone or other steroids

- At least 4-6 weeks since flutamide with evidence of PSA progression required (if
possible)

- At least 28 days since radiotherapy

- At least 28 days since major surgery