Natural History Study of Monoclonal B Cell Lymphocytosis (MBL), Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL), Lymphoplasmacytic Lymphoma (LPL)/Waldenstrom Macroglobulinemia (WM), and Splenic Marginal Zone Lymphoma (SMZL)

Background The development of new technologies now allow scientists to investigate the molecular basis and clinical manifestations of monoclonal B cell lymphocytosis (MBL), chronic lymphocytic leukemia(CLL)/small lymphocytic lymphoma (SLL), lymphoplasmacytic lymphoma (LPL)/Waldenstrom macroglobulinemia (WM), and splenic marginal zone lymphoma (SMZL). Applying these methods in a natural history study can help identify processes involved in disease progression, and possibly lead to the discovery or validation of treatment targets. Objectives Study the history of MBL/CLL/SLL/LPL/WM/SMZL in patients prior to and after treatment. Characterize clinical, biologic and molecular events of disease stability and progression of patients enrolled on this protocol. Eligibility: * Diagnosis of CLL/SLL and on treatment/previously treated/nearing treatment * Diagnosis of LPL/WM * As of February 5, 2025, patients with MBL and SMZL will no longer be enrolled. * Age greater than or equal to 18 years. * ECOG performance status of 0-2. Design Patients are typically followed every 6 to 24 months in the clinic and have blood drawn. Patients may be asked to undergo additional testing, including bone marrow biopsy and aspiration, lymph node biopsy, positron emission tomography, and CT and MRI scans. Some of these tests (e.g., blood draw) may be required to monitor CLL/SLL and LPL/WM. Other tests (e.g., lymph node biopsy) may not be clinically indicated, but patients may be asked to undergo these procedures for research purposes. No treatment will be administered on this study. If a patients requires treatment for their cancer, available NIH clinical trials and alternative treatment options will be discussed with the patient.