HOXA4 and B-cell chronic lymphocytic leukemia: This is further supported by the observation of frequent hypermethylation of the HOXA cluster and hypomethylation of Wnt ligands in CLL patient samples.31 Subsequently, subclonal cell populations with biallelic methylation of HOXA4 would be selected due to the increased pro-survival Wnt signalling, with selection pressure significantly increased with therapeutic intervention.