Phenylbutyrate in Treating Patients With Refractory Solid Tumors or Lymphoma

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