DISEASE CHARACTERISTICS: Histologically confirmed malignancy that is refractory to standard therapy or for which no standard therapy exists Low grade lymphoproliferative disorder defined as: Chronic lymphocytic leukemia/small lymphocytic lymphoma Waldenstrom's macroglobulinemia Follicular lymphoma (small cleaved, mixed, and large cell) Mantle cell lymphoma Prolymphocytic leukemia (T and B type) Cutaneous T cell non-Hodgkin's lymphoma Marginal zone lymphoma and variants Hairy cell leukemia variants MALT lymphomas Patients with low grade lymphoproliferative disorders must have received at least 1 or more treatment regimens and must not be eligible for potentially curative treatments (i.e., bone marrow transplantation) No HTLV-1 associated lymphomas, Burkitt's or small non-cleaved lymphomas, transplant related lymphoproliferative disorders, Hodgkin's disease, diffuse large cell lymphoma, or multiple myeloma No primary brain tumors or history of brain metastases