OBJECTIVES:~Primary~Conduct a pilot study investigating the effects of Polyphenon E, a compound extracted from green tea which contains epigallocatechin-3-gallate (EGCG), on monoclonal protein levels in patients with monoclonal gammopathy of undetermined significance and/or smoldering multiple myeloma.~Secondary~Collect, process, and store blood and marrow specimens for future measurement of the biologic effects of Polyphenon E on the plasma cells of these patients by utilizing proteosome activity assays and gene expression profiling.~OUTLINE: Patients receive oral green tea catechin extract (Polyphenon E) daily on days 1-28. Treatment repeats every 28 days for up to 6 courses in the absence of disease progression or unacceptable toxicity.~Patients may undergo blood, urine, and bone marrow sample collection periodically for correlative laboratory studies. Samples are analyzed for monoclonal protein (M-protein) levels, proteosome function, and gene expression.
RATIONALE: Green tea extract contains ingredients that may prevent or slow the growth of monoclonal gammopathy of undetermined significance and/or smoldering multiple myeloma.~PURPOSE: This phase II trial is studying how well green tea extract works in treating patients with monoclonal gammopathy of undetermined significance and/or smoldering multiple myeloma.