The observed shortening of telomere length in CLL patients was in line with other classical biological factors of CLL, including unmutated immunoglobulin variable region genes (UM-IGVH), CD38 and ZAP-70 positivity (>30%) and short (<6 months) lymphocyte doubling time [29]. Here, ZAP70 is linked to B-cell chronic lymphocytic leukemia.