DNA methylation was studied within the promoter region of the CRY1 gene (Figure S1) employing sequencing of cloned PCR products generated from bisulphite-modified DNA extracted from immunomagnetically purified CD19+ B cells from the peripheral blood of CLL (N = 14) and normal donors (N = 4). This evidence concerns the gene CRY1 and B-cell chronic lymphocytic leukemia.