ABCC4 and cancer: Our lab has previously used Affymetrix microarray analysis to identify several androgen-regulated genes, including Soluble Guanyl Cyclase α1 (sGCα1), ETV1, and Multi-Drug Resistant Protein 4 (MRP4) which have been shown to have important pro-cancer roles in prostate cancer cells (Cai et al., 2007a, 2007b, 2006; Cai, Hsieh & Shemshedini, 2007).