AR and prostate cancer: Later genome wide chromatin-immunoprecipitation experiments (ChIP-seq) for AR, ER, and FOXA1 in breast and prostate cancer cell lines and primary tumor tissue revealed a high level of co-occupancy between this pioneer factor and its respective nuclear receptor, presumably mediated by the forkhead motif found at AR and ER binding events (Carroll et al., 2006; Wang et al., 2007; Jia et al., 2008; Hurtado et al., 2011).