Significant change in ZAP‐70 expression during the course of chronic lymphocytic leukemia

Abstract

In contrast to commonly accepted opinion, significant change in ZAP-70 expression in time was detected in a substantial proportion of our patients with CLL. While the conversion to ZAP-70 negativity was found predominantly in patients with stable disease, change to positivity was typical in patients with unmutated IgVH genes at the time of progression or relapse. Based on our pilot results, repeated assessment of ZAP-70 expression might be especially useful at the time of progression or relapse in patients who were initially ZAP-70-negative.