HOXA9 and cancer: Loss of H2AK119ub was significantly associated with increased transcription in malignant and non-transformed BcorΔE9-10 KL cells and we identified putative direct targets of PRC1.1 including Hoxa7, Hoxa9 and Zfp36l1. The contribution of Hoxa7 and 9 to cancer are well established29,59 and Zfp36l1, which encodes butyrate response factor 1, has been implicated in myeloid differentiation and negative regulation of the anti-apoptotic protein BCL232,60.