The protease MALT1 is a signaling protein that drives NF-κB (nuclear factor-κB) dependent gene expression, which is associated with tumor cell proliferation, survival and metastasis. MALT1 is frequently activated in B cell lymphoma and is a potential therapeutic target. However, its role in solid cancers is much less clear. Based on some promising initial findings, we hypothesize a novel role of MALT1 in prostate cancer. The major objectives are: 1. to characterize the molecular and functional role of constitutive MALT1 activity in prostate cancer cell proliferation, survival and migration; 2. to identify the upstream molecules that activate MALT1 in prostate cancer cells; 3. to characterize the physiological role of MALT1 in prostate cancer tumor formation and metastasis using cellular and mouse models of prostate cancer combined with genetic and pharmacological targeting of MALT1.