SFRP4 and B-cell chronic lymphocytic leukemia: Consistently the promoter of genes coding for Wnt pathway inhibitors including WIF1, DKK3, APC, SFRP1, SFRP2, SFRP4, and SFRP5 are frequently hypermethylated and consequently downregulated in samples from CLL and ALL (Roman-Gomez et al., 2004; Martin et al., 2008; Rahmatpanah et al., 2009).