White Button Mushroom Extract in Treating Patients With Recurrent Prostate Cancer After Local Therapy

OBJECTIVES: Primary * To assess the feasibility and toxicity of prolonged white button mushroom extract therapy at six different dose levels in patients with biochemically recurrent prostate cancer after local therapy. Secondary * To analyze the effect of this regimen on a variety of biomarkers including testosterone, dihydrotestosterone, dehydroepiandrosterone, estrogens, aromatase, parameters of immune function, and circulating tumor cells. * To assess the effect of this regimen on PSA kinetics as a measure of disease activity in these patients. OUTLINE: This is a dose-escalation study. Patients receive oral white button mushroom extract twice daily on days 1-28. Courses repeat every 4 weeks in the absence of disease progression or unacceptable toxicity. Blood and urine samples are collected periodically for pharmacokinetic, pharmacodynamic, and immunologic correlative studies. Plasma and urine samples are analyzed for quantification of conjugated unsaturated fatty acids via gas chromatography-mass spectometry. Plasma samples are analyzed for inhibition of aromatase via aromatase activity analysis and the effect of treatment on immune cytokines levels via immunobiologic assays. Peripheral blood mononuclear cells are analyzed for the effect of treatment on immune cell subsets and NK cell function via multi-parameter flow cytometry; effect of treatment on NK cell activation status via staining method; and measurement of circulating tumor cells via fluorescence microscopy, fiber-optic array scanning technology (FAST), or high-speed flow cytometry. Additional serum samples are collected for future studies. Patients complete a diary listing days of administration of treatment and side effects.