Correspondence

Correction

ZAP-70 in Chronic Lymphocytic Leukemia

N Engl J Med 2003; 349:506-507July 31, 2003

Article

To the Editor:

Crespo et al. (May 1 issue)1 present informative data on ZAP-70 as a surrogate prognostic marker for chronic lymphocytic leukemia (CLL). The patients in their study had heterogeneous backgrounds and may have been treated by different treatment strategies according to their age and disease status. Elderly patients with advanced or refractory CLL may have received less intensive treatment than others, leading to a poorer prognosis. Because treatments differ greatly in their effects on overall survival, there may have been a selection bias in the study. The authors have not provided sufficient information on these variables. Clinicians will appreciate it if the authors can share the data on treatments.

Naoko Murashige, M.D.
Masahiro Kami, M.D.
Yoichi Takaue, M.D.
National Cancer Center Hospital, Tokyo 104-0045, Japan
mkami@ncc.go.jp

1 References

1. 1

   Crespo M, Bosch F, Villamor N, et al. ZAP-70 expression as a surrogate for immunoglobulin-variable-region mutations in chronic lymphocytic leukemia. N Engl J Med 2003;348:1764-1775
   Full Text | Web of Science | Medline

Author/Editor Response

Murashige et al. make interesting comments concerning the clinical characteristics and treatment of the patients in our study. At our institution, patients in whom Binet stage A CLL is diagnosed do not receive therapy unless they meet criteria for active CLL.1 Treatment has, of course, varied over the years, from chlorambucil to fludarabine-based combination regimens. Interestingly, in our series, only 3 of the 18 patients with Binet stage A disease and low ZAP-70 expression required treatment, whereas 20 of the 26 patients with high ZAP-70 expression were treated. The main clinical variables, including age, did not differ between the two groups. Thus, with ZAP-70 analysis we were able to identify a group of patients with a bad prognosis, irrespective of the clinical stage. Finally, the relation among ZAP-70 expression, clinical variables, and survival should be assessed in larger series of patients.

The source of the monoclonal anti–ZAP-70 antibody used for flow cytometry was Upstate Biotechnology.

Francesc Bosch, M.D.
Neus Villamor, M.D.
Emili Montserrat, M.D.
Hospital Clinic, Barcelona 08036, Spain
fbosch@clinic.ub.es

1 References

1. 1

   Cheson BD, Bennett JM, Grever M, et al. National Cancer Institute-sponsored Working Group guidelines for chronic lymphocytic leukemia: revised guidelines for diagnosis and treatment. Blood 1996;87:4990-4997
   Web of Science | Medline