Double minute chromosomes and homogeneously staining regions in tumors taken directly from patients versus in human tumor cell lines

Patients with follicular lymphoma and a low tumor burden have a median overall survival of more than 10 years. Toxic conventional chemotherapy regimens are inappropriate in these patients, as they do not improve overall survival and the patients do not require palliation of symptoms. However, as most of these patients will ultimately die of their lymphoma, new therapies, with curative intent, are required. Rituximab is a human-mouse chimeric monoclonal antibody that has shown efficacy in patients with non-Hodgkin's lymphoma (NHL). The benign tolerability profile of rituximab makes it a suitable candidate for first-line treatment of follicular NHL patients with a low tumor burden. In a trial of 49 patients, 73% achieved a clinical response (26% complete response) with rituximab treatment. Molecular studies showed that 57% of patients achieved molecular remission (clearance of the bcl-2 molecular translocation from the blood, evaluated by polymerase chain reaction), 62% of these remaining bcl-2- for at least 1 year. There was a good correlation between molecular and clinical responses, with patients failing to achieve a molecular response at higher risk of disease progression. Rituximab monotherapy is therefore an effective and well-tolerated treatment for patients with low-grade lymphoma and a low tumor burden.