Findings that could be useful in staging and correlating methylation with pre-existing prognostic factors in CLL include RRM1/2 expression, the promoter methylation status that correlated with lymphadenopathy, 17p gene deletion, Rai stage, and trisomy 12 [39], and the documentation of hypermethylation at specific ITGA4 CpG sites in del13q14+ samples [70]. Here, RRM1 is linked to B-cell chronic lymphocytic leukemia.