PCAT1 and cancer: Curiously, PCAT-1 defined a subset of aggressive cancers with low expression of the epigenetic regulator EZH2, a component of the PRC2. Besides pointing to PRC2-regulated selected target genes, ChIP (chromatin immunoprecipitation) revealed that the PRC2 complex directly binds to the promoter region and represses PCAT-1, and RIP (RNA immunoprecipitation) showed that PCAT-1 transcript reciprocally binds PRC2 in a feedback inhibition loop [24].