When we restricted our analysis to genes with a known role in B-cell biology and/or CLL pathogenesis (Fig. 5d), we observed a highly specific association of CD22 (which codes for an inhibitory receptor involved in B-cell receptor signalling) with mCLL, whereas CD38 and ZAP70 were preferentially associated with uCLL. This evidence concerns the gene CD22 and B-cell chronic lymphocytic leukemia.