SPEN and neoplasm: In addition, among the 20 most PE5 up-regulated genes (Table S1, Supplementary Data) some are candidate tumor suppressors: Leucine rich repeat containing 2 (LRRC2) [87,88], Replication protein A4, 30kDa (RPA4) [89,90], Protein phosphatase 6, regulatory subunit (PPP6R1) [91,92], Spen homolog, transcriptional regulator (Drosophila) (SPEN) [93], RAP1GTPase activating protein (RAP1GAP) [94] and cytokine inducible SH2-containing protein (CISH) [95].