Predicting Progression--ZAP-70 in CLL

The harder we look, the more we find. Diagnoses of chronic lymphocytic leukemia (CLL) are becoming more common because we are looking harder. With sensitive techniques, a monoclonal population of B lymphocytes that is indistinguishable from CLL cells may be found in the blood of 3.5 percent of persons older than 40 years of age. Even without such sophisticated methods, simple immunophenotyping, which is available to all, easily singles out CLL from the many other causes of slight lymphocytosis. Such a finding will never have clinical effects in most people — they will die with it rather than from it . .