The NF-κB family of transcription factors has been shown to be constitutively activated in various human malignancies, including leukemias, lymphomas, and a number of solid tumors. NF-κB is hypothesized to contribute to development and/or progression of malignancy by regulating the expression of genes involved in cell growth and proliferation, anti-apoptosis, angiogenesis, and metastasis. Prostate cancer cells have been reported to have constitutive NF-κB activity due to increased activity of the IκB kinase complex. Furthermore, an inverse correlation between androgen receptor (AR) status and NF-κB activity was observed in prostate cancer cell lines. NF-κB may promote cell growth and proliferation in prostate cancer cells by regulating expression of genes such as c-myc, cyclin D1, and IL-6. NF-κB may also inhibit apoptosis in prostate cancer cells through activation of expression of anti-apoptotic genes, such as Bcl-2, although pro-apoptotic activity of NF-κB has also been reported. NF-κB-mediated expression of genes involved in angiogenesis (IL-8, VEGF), and invasion and metastasis (MMP9, uPA, uPA receptor) may further contribute to the progression of prostate cancer. Constitutive NF-κB activity has also been demonstrated in primary prostate cancer tissue samples and suggested to have prognostic importance for a subset of primary tumors. The limited number of samples analyzed in those studies and the relative lack of NF-κB target genes identified in RNA expression microarray analyses of prostate cancer cells suggest that further studies will be required in order to determine if NF-κB actually plays a role in human prostate cancer development, and/or progression, and to characterize its potential as a therapeutic target. © 2003 Wiley-Liss, Inc.